Comparison of rhizosphere microbial community of hybrid rice
cultivars based on phospholipids fatty acid analysis
Y. Zhu1#, G. Hu1#, B. Liu1*, H. Xie2, X. Zheng1 and J. Zhang2
1 Agricultural Bio-resources Institute, Fujian Academy of Agricultural Sciences, Fujian, China
2 Fuzhou Sub-center of National Center of Rice Improvement and Rice Research Institute, Fujian
Academy of Agricultural Sciences, Fujian, China.
# These
authors contributed equally to this work.
* Correspondence
B. Liu, Agricultural Bio-resources Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350003,
Fujian, China
Tel.: +86 591 87864601
Fax: +86 591 87864601
Email: liubofaas@163.com
1
Abstract: This paper deals with the variation in productive characteristics and rhizosphere microbial community structure among Chinese
hybrid rice cultivars. The intrinsic relationship between variety and the rhizosphere microbial community structure of rice was also analyzed.
Three series of new-breeding Chinese hybrid rice cultivars were tested in the experiment, IIyouming86 (II-32A/Minghui86), IIyouhang1hao
(II-32A/Hang1hao) and IIyouhang2hao (II-32A/Hang2hao) with II-32A as female parent, XinyouHK02 (XinA/HK02) and YiyouHK02
(YXA/HK02) with HK02 as male parent, Chuanyou167 (ChuanxiangA/MR167) and 44you167 (Hunan44A/MR167) with MR167 as male
parent. The microbial community structures in rhizosphere of different hybrid rice cultivars were determined with phospholipid fatty acids
(PLFA) analysis. Forty PLFA biomarks were detected in all and the PCA analysis of the PLFA composition showed that the first two
principal components PC1 and PC2 account for 69.62% and 17.82% of the variation. Bacterial PLFAs were more abundant than fungal and
actinomycetic PLFAs in paddy soil of the hybrid rice tested. It was observed that microbial biomass revealed as PLFAs amount had positive
correlation with the rice grain number per spike (R2=0.801**), seed setting rate (R2=0.845**) and yield (R2=0.909**), and had negative
correlation with the rice plant height (R2=-0.969**). Based on the characteristics of PLFAs and the biological traits of rice, the results of
cluster analysis suggested that microbial community structure and activity in rhizosphere were associated with genetic background of the rice
cultivar.
Key words: Rice, Productive characteristics, Rhizosphere Microorganism, Phospholipid Fatty Acid.
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Introduction
Rice (Oryza sativa L.) is a staple food in China, contributing 40% to the total calorie intake of Chinese people. However,
rapid population growth and economic development had been posing a growing pressure for food production (Zhang 2007).
In addition, the continuing reduction of cultivated land area and the serious lack of water resource during the past three
decades appealed to develop and extend super rice varieties or hybrids with wide adaptation and super high yielding potential
(Chen et al. 2007). To meet the need of the food consumption, hybrid rice that has a yield advantage of 10-20% over
conventional varieties was developed and commercially grown, and has commanded about 50% of the total rice area in China.
Now, the rice yield has risen to about 6.0 t ha-2 that was 2.0 t ha-2 and 3.5 t ha-2 in the 1960s and 1970s (Cheng et al. 2007).
Recently, super hybrid rice has been generally exploited through systematic researches of growth and development, dry
matter production, tillering ability, root activity, optimum locations and seasons, high yielding path and the technique system
for super hybrid rice, the physiological basis of high yielding formation, cultivation environments and agronomy techniques
under the cultivation conditions of single seedling and sparse planting and increase in nitrogen fertilizer (Wang et al. 2002).
It is well known that soil microorganisms that colonize the rhizosphere assist plants in the uptake of several vital
nutrients, such as phosphorous, potassium and nitrogen, from the soil (Cocking 2003; Ikeda et al. 2006). The rice field is a
unique agro-ecosystem, where the field is maintained under flooded conditions during most of the period of rice cultivation,
and is left under drained conditions during the off-crop season (Kimura and Asakawa 2006). Numerous studies have been
carried out on microbial community structure of irrigated rice system, and most of them were focused on polluted soil, soil
management practices, nutrient cycling and ecology, and various habitats (Kong et al. 2008; Zhang et al. 2007). However,
there were quite few studies on the soil microbial community structure of different hybrid rice cultivars. The composition and
amount of microorganisms presented in the rhizospheres of rice cultivars might differ due to variations in the quantity and
quality of compounds exuded by the different plants.
Recent methodological advanced such as analysis of DNA and the phospholipid fatty acids (PLFAs) as well as
cultivation on Biolog Gram-negative (GN)-plates allowed us to obtain more detailed information on soil microbial activities
and community structures (Zhang 2007). Polar lipids in soil microbes were primarily phospholipids. Thus determination of
PLFAs could provide a quantitative measurement of microbial biomass and information on community structure composition
of microorganism with specific PLFAs markers (Mubyana-John et al. 2007). For example, (Zhang et al. 2007) investigated
the microbial communities under irrigated rice cropping with different fertilizer treatments by using PLFA profile method.
(Kimura and Asakawa 2006) compared the community structures of microbiota at main habitats in rice field ecosystems
based on phospholipids fatty acid analysis. (Lu et al. 2007) revealed the spatial variation of active microbiota in the rice
rhizosphere by in situ stable isotope probing of phospholipid fatty acids.
The present study compared productive characteristics of seven new Chinese hybrid rice cultivars, in which three of
them were from a same female parent and four from two male parents. The rhizosphere microbial community structures of
different rice cultivars were also studied by measuring the PLFAs compositions. Furthermore, the inherent correlation among
the cultivar characteristics, the community structure and cultivar were evaluated, such as the rice growth ability and the
genetic relationship. Our findings are helpful to our further understanding of hybrid rice cultivation and varietal improvement
in China.
Materials and Methods
Field experiment
The trials were conducted at No.3 field of Rice Experimental Station, Rice Research Institute, Fujian Academy of
Agricultural Sciences, Shaxian, Fujian, China. Shaxian (26°24’N, 117°48’E, 119 m above sea level) is in the Subtropical
Zone and continental monsoon area with the average annual temperature about 15.6°C-19.6°C and a frost-free period of
270-300 days. The annual precipitation is about 1,661.9 mm with above 50% in May and June. The field area was 2,001 m2
with 2 m protection rows around and the experiment was carried out from May to September, 2008. Three series of hybrid
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rice cultivars were used in this experiments, IIyouming86 (IIyou/Minghui86), IIyouhang1hao (IIyou/Hang1hao) and
IIyouhang2hao (IIyou/Hang2hao) with II-32A as female parent, XinyouHK02 (XinAn/HK02) and YiyouHK02
(YiXiangA/HK02) with HK02 as male parent, Chuanyou167 (ChuanxiangA/MR167) and 44you167 (Hunan44A/MR167)
with MR167 as male parent.
The rice seeds were sown on sowing 16th May under dry condition in greenhouse, and the seedlings were transplanted
on 26th June. Plot size was 3.6 m2 with row length of 4 m, plant-to-plant of 13 cm and row-to-row spacing of 30 cm in each
plot. The plants were singly cultivated. The experiment was set up in a randomized block design with three replications.
Seven rice cultivars had total 21 plots. Standard cultivation practices as commonly performed in the area were followed in all
experimental plots. For yield estimate, early-maturing rice cultivars were harvested on 25th September, while the
middle-maturing cultivars on 22nd October and late-maturing cultivars on 8th November. Ten plants at the center of each
plot were selected and the agronomic parameters were recorded, including grain number per spike, seed setting rate (%),
plant height (cm) and paddy yield (kg 666 m-2).
Soil sampling
For PLFAs analysis, sampling was conducted on 27th July at rice booting stage by root-shaking method. After the plant
with root was dug out, the soil combining loose on the root were removed by shaking. And then, the soil tight attached on the
root within 0-4 mm was brushed as rhizosphere soil sample. Five plants were sampled by quincunx-sampling method in each
plot. The soil samples of each plot were mixed and transported by plastic bag to the laboratory at the same day. Each rice
cultivar had three replications. The rhizosphere samples were air-dried at room temperature till the soil moisture was in the
range of 25-30%. Afterwards, the samples were filtered with 2 mm sieve and then maintained at -80°C until phospholipid
extraction.
PLFA analysis
The phospholipid fatty acids extraction procedure employs a mild alkaline methanolysis method developed by Dr. Rhae
Drijber, University of Nebraska, Lincoln, NE (Schutter and Dick 2000). The particular steps were as follow. In the first step,
15 ml of 0.2 M KOH in methanol were added to a 50-ml Teflon-lined, screw-cap glass centrifuge tube containing 3 g of soil.
The contents of the tubes were mixed and incubated at 37°C for 1 h, during which ester-linked fatty acids were released and
methylated. Samples were vortexed every 10 min during the incubation period. In the second step, 3 ml of 1.0 M acetic acid
were added to neutralize the pH of the tube contents. PLFAs were partitioned into an organic phase by adding 10 ml of
hexane followed by centrifugation at 2000 r min-1 for 15 min. and then the hexane was transferred to a clean glass test tube
and evaporated under a stream of N2. Finally, PLFAs were dissolved in 0.5 ml 1:1 hexane:methyl-tert butyl ether and
transferred to a GC via and kept at 4°C until analysis.
All samples were analyzed on automated Sherlock® Microbial Identification System (MIDI, Newark, DE, USA). The
system is based on GC-FID platform employing HP 6890 Series GC with equivalent column ULTRA 2 (25 m × 0.2 mm ×
0.33 μm) operated under default conditions. The shorthand nomenclature common in biochemistry and fully supported by the
Sherlock® & MIDI was used for identification of the fatty acids in the form as <number of carbon atoms>:<number of
double bonds> ω <position of double bonds from methyl end of molecule>. Prefixes i, a and cy are used for iso-, anteiso and
cyclopropyl- fatty acids. Hydroxy groups are indicated by ‘OH’. 10Me denotes a methyl group on the 10th carbon from
carboxylic end of molecule. Methyl nonadecanonate (C19:0) was used as the internal standard and the PLFAs were expressed
as equivalent peak responses to the internal standard. The total microbial biomass was expressed as µg PLFAs g-1 dry weight
soil. PLFAs that correspond to carbon chain lengths of 12-20 carbons are generally associated with microorganisms. PLFAs
used as markers for microorganism are list in Table 1.
Statistical analysis
Analysis of variance (ANOVA) was performed by using Fisher’s least significant difference comparison of means
(LSD). In order to find out the predominant PLFA in the rice rhizosphere, the content of individual fatty acid methyl esters
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was analyzed with Principal component analysis (PCA). Mean coordinates of individuals were calculated for the first two
principal components (PC1 and PC2). PLFAs were assigned to the positive and negative parts of the principal components
according to the sign of their eigen values. To study the variation among productive characteristics of different hybrid rice
cultivars, the productive parameters of rice were submitted to hierarchical cluster analysis with unweighted pair-group mean
average method (UPGMA) by using the seven rice cultivars as samples, the productive characteristics as indexes, and
Lance-William distance as similarity scale. To compare the rhizosphere microbial community structures of the tested rice, the
same cluster process was carried out by using the seven rice cultivars as samples and the contents of PLFAs as indexes. The
correlation analysis was conducted using the PLFAs’ content and the plant characteristics (grain number per spike, seed
setting rate, paddy yield and plant height) of rice as indexes. The procedure was introduced Spearman index as the correlation
index. All the statistical analysis was performed using software SPSS version 17, Chicago, Ill.
Results and Discussion
Productive characteristics
The productive characteristics of the seven new hybrid rice cultivars tested are listed in Table 2. Field experiment
showed that the rice cultivar Chuanyou167 and 44you167 of you167 series had significant higher grain number per spike,
seed setting rate and yield than three rice cultivars of IIyou series and two cultivars of HK02 series. However, the plant
heights of HK02 series were highest, following by IIyou series; the shortest were those of you167 series. For example,
44you167 had grain number per spike, seed setting rate, yield and plant height as 180.71, 94.88%, 8948.40 kg ha-1 and 110
cm, while YiyouHk02 had those parameters as 123.50, 72.71%, 7564.50 kg ha-1 and 130 cm.
PLFAs detected in rhizosphere
The rhizosphere of each hybrid rice cultivar contained various PLFAs composed of saturated, unsaturated,
methyl-branched and cyclopropane fatty acids (Table 3). Forty PLFAs with chain lengths ranging from C12 to C20 were
identified, including the PLFAs biomarks of 16:0 and 18:0 indicative of bacteria, 10Me18:0, 10Me16:0 indicative of
actinomycetes, 18:1ω9с, 18:3ω6с(6,9,12) and 16:1ω9с indicative of fungi, i14:0, a14:0, i15:0, a15:0, i16:0, a16:0, i17:0,
a17:0, 10Me 17:0, i18:0 indicative of gram-positive bacteria, 12:0, 14:0, 15:0 3OH, i15:0 3OH, 15:0 2OH, 16:1 2OH, i17:0
3OH, 17:0, 17:1ω8с, cy17:0, 18:1ω5с, 18:1ω7с, i18:1 H, cy19:0ω8с indicative of gram-negative bacteria, 16:1ω5с indicative
of methane-oxidizing bacteria, 10Me16:0 indicative of sulfate-reducing bacteria, 14:1ω5с indicative of Desulfosporomusa
polytropagen, 20:1ω9 indicative of Arthropoda, 20:4ω6,9,12,15с indicative of protozoa, and 15:1 ISO G, 16:0 N ALCOHOL,
16:1 ISO G, 11Me 18:1ω7с, 20:0 indicative of all non-special microbial.
Rhizosphere Soil microbial community structure
An amount of bacteria that obtained gram-positive bacteria, gram-negative bacteria, sulfate-reducing bacteria and
methane-oxidizing bacteria, also a number of fungi, actinomycetes, arthropoda and protozoa were living in the rhizosphere of
rice based on the outcome of PLFAs above. PLFAs data were processed using the principal component analysis (PCA).
Results presented in Fig. 1. PCA produced two principal components (PC) which accounted for 87.44% of the total
variability. PC1 accounted for 69.62% of the variance and PC2 was responsible for explaining 17.82% of the variation,
respectively. PLFAs 16:0, 18:1ω7с, 18:1ω9с and 10Me16:0 were positively correlated with PC1. PLFAs a15:0, i16:0, a16:0,
i17:0 3OH, i18:0 and i18:1 H were highly negatively correlated with PC1. PLFAs 15:0 2OH, i15:0 3OH, i17:0 3OH, i18:0
and i18:1 H were highly positively correlated with PC2. PLFAs 12:0, 14:1ω5с, 15:0 2OH, i15:0, 16:1 ISO G and 20:1ω9с
were highly negatively correlated with PC2.
In general, 16:0, 18:1ω9с and 10Me17:0 which represented bacteria, fungi and actinomycetes were chiefly responsible for
the variances, which indicated they were the primary compositions on the microbial community. Therefore, the contents of
PLFAs 16:0, 18:1ω9с and 10Me17:0 could be used as the abundant indexes of bacteria, fungi and actinomycetes to analyze
the structure of the microbial community in rice rhizosphere. The rhizosphere microbial community structures of different
hybrid rice cultivars were showed in Fig. 2. On the whole, bacteria were most predominant followed by fungi and
actinomycetes as the second and third abundant microorganism in the rice rhizosphere.
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Relationship among cultivar, productive characteristics and rhizosphere microbial community structure of rice
By using unweighted pair-group mean average (UPGMA) method, cluster analysis results of the seven hybrid rice
cultivars based on productive characteristics (Table 2) and on soil PLFAs analysis (Table 3) were performed in Figure 4. The
seven rice cultivars could be divided into two groups at 0.18 of according to their biological features (Fig. 4a). The first group
contained the two subgroups. One subgroup was the IIyou series that included IIyouming86, IIyouhang1hao and
IIyouhang2hao with middle grain number per spike (143-146), seed setting rate (74-80%) and yields (7800-8000 kg ha-1) as
well as middle plant height (122-125 cm); the other subgroup was HK02 series that obtained XinyouHK02 and YiyouHK02
with grain number per spike (<130), seed setting rate (<72.72%) and yields (<7800 kg ha-1) as well as highest plant height
(>125 cm). The second group was you167 series with highest grain umber per spike (>172), seed setting rate (>92%) and
yields (>8600 kg ha-1) as well as lowest plant height (<112 cm). The results indicated that the productive characteristics of
rice in relation to plant variety and their genetic background.
Similarly, the statistic results based on PLFAs analysis showed that the tested rice cultivars could be also clustered into
two groups at 3.68 of Lance-William distance (Fig. 4b). The first group consisted of two subgroups, included rice cultivars of
HK02 series and IIyou series, respectively. The hybrid rice Chuanyou167 and 44you167 of you167 series were involved in
the second group. Because the PLFAs composition reflected the microbial status in soil, it could be concluded that the
microbial biomass and community structure in rhizosphere of rice cultivars in relate to hybrid genetic background. For
example, HK02 series rice had of lowest PLFAs biomasses (<5000 µg g-1), while those of IIyou series had middle values of
PLFAs biomasses (5100-5600 µg g-1) and you167 series and highest PLFAs biomasses (>7000 µg g-1).
On the other hand, based on the data showed in Table 2 and 3, the amount of PLFAs biomasses in the rhizosphere of
hybrid rice was found to had positive correlation with the rice grain number per spike (R2=0.801**), seed setting rate
(R2=0.845**) and yield (R2=0.909**), and had negative correlation with the rice plant height (R2=-0.969**).
Discussion
Heterosis has been successfully exploited on a large scale in rice, which is a self-pollinated crop. The selection of
parental lines plays a vital role in developing ideal combinations (Wang et al. 2006). In this study, the seven hybrid rice
cultivars that bred by different parents performed high varied in their productive traits, which indicated the genetic diversity
in hybrid breeding. However, the cluster analysis mentioned that genetic background had remarkable effect on the rice
agronomic characteristics. For example, rice cultivars of Chuanyou167 and 44you167 derived from male parent MR167 had
significant higher yield and lower plant height than the other three rice cultivars bred from female parent IIyou and two rice
cultivars from male parent HK02.
Owing to leakage of O2 and organic substances from roots, the rice roots and the rhizosphere provide niches for diverse
organisms performing various biogeochemical processes (Kimura and Asakawa 2006). The productivity of soil system is
known to depend greatly upon the structure and functions of soil microbial communities, which regulate and influence many
ecosystem processes such as nutrient transformation, litter decomposition, soil structure and plant health (Garbeva et al.
2004). By using PLFAs as specific markers, gram-positive bacteria, gram-negative bacteria, methane-oxidizing bacteria,
sulfate-reducing bacteria, fungi, actinomycetes, Arthropoda and protozoa were detected at paddy soil in this experiment. In
generally, bacteria were most abundant in rice rhizosphere than fungi and actinomycetes. Both fungi and actinomycetes play
a major role in decomposition of organic residues high in cellulose and lignin (Mubyana-John et al. 2007). Therefore, it could
be concluded that bacteria was crucial in nutrient holding capacity for hybrid rice.
Bacterial communities in root-associated habitats respond with respect to density, composition and activity to the
abundance and great diversity of organic root exudates, eventually yielding plant species-specific microfloras (Griffiths et al.
2007). Arab et al. (2001) used PLFA method to determine the rhizosphere specific microbial communities of two wheat
cultivars, and the results notified the rhizosphere wheat cultivar Bohouth-6 involved larger amount of Pseudomons spp. than
cultivar Salamouni. Siciliano et al. (1998) reported that the differences in the microbial communities were associated with the
6
roots of different cultivars of canola (rape, Brassica spp.) and wheat (Triticum spp.). Briones et al. (2002) compared the
activities and diversities of ammonia-oxidizing bacteria (AOB) in the root environment of different cultivars of rice and the
results indicated marked difference despite identical environment conditions during growth. The composition and amount of
microorganisms present in the rhizospheres of the hybrid rice cultivars tested also differed significantly, which may due to
variations in the quantity and quality of compounds exuded by the different plants (Söderberg et al. 2002). Furthermore,
because the selection of parental lines played a vital role in developing ideal hybrid rice combinations, the identification of
heterotic groups and patterns among breeding populations and lines provides fundamental information in order to help the
plant breeders to gain more information on heterosis (Chen et al. 2007). The difference of rhizosphere microbial communities
indicated by PLFAs contents was found to be in relation to the rice hybrid genetic background, which might be used as a new
approach to identify their parental lines.
Soil microbial biomass is considered to act both as the agent of biochemical changes in soil and as a repository of plant
nutrients in agricultural ecosystems (Zhang and Wang 2005). For instance, Lu et al. (2006) studied the structure and activity
of bacterial community inhabiting rice roots and the rhizosphere and suggested that cycling of iron and sulfur is active in the
rhizosphere. The rice cultivar 44you167 that had highest yield was revealed to possess most amount of microbial biomass in
rhizosphere. Therefore, it could be presumed that the plant variety shape soil- and plant-associated habitats and modify the
compositions and activities of their microbial communities, which in turn bear upon the quality of their environment, the
growth of plants, and the production of root exudates (Wieland et al. 2001). Consequently, different rhizosphere microbial
communities are associated with different plants (Kremer et al. 1990).
Acknowledgements The present investigation was supported by the National High Technology Research and
Development Program ("863" Program) of China (2006AA100101 and 2006AA10A211).
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Zhang, P., Zheng, J., Pan, G., Zhang, X., Li, L., and Tippkotter, R. 2007. Changes in microbial community structure and function within
particle size fractions of a paddy soil under different long-term fertilization treatments from the Tai Lake region, China. Colloids Surf B
Biointerfaces. 58(2): 264-270. doi:10.1016/j.colsurfb.2007.03.018.
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[pii]10.1073/pnas.0708013104.
Zhang, Q.C., and Wang, G.H. 2005. Studies on nutrient uptake of rice and characteristics of soil microorganisms in a long-term fertilization
experiments for irrigated rice. J Zhejiang Univ Sci B. 6(2): 147-154. doi:10.1631/jzus.2005.B0147.
8
Table 1. PLFAs used as markers for microorganism
microorganism
PLFAs maker
Reference
bacteria
i15:0, a15:0, 15:0, 16:0, 16:1ω5, 16:1ω9, i17:0, a17:0,
(Frostegfird and Baath 1996; Hill et al. 2000; Myers
17:0, 18:1ω7t, 18:0, 18:1ω5, i19:0, a19:0
et al. 2001; Waldrop et al. 2000)
Fungal
18:1ω9с,
18:3ω6с(6,9,12),
18:2ω6c,
18:3ω6c,
(Kourtev et al. 2002; Olsson et al. 1999)
18:3ω3c, 16:1ω9с
Actinomycetic
10Me 17:0, 10Me18:0, 10Me16:0
(Kourtev et al. 2002)
Gram-positive bacteria
i14:0, a14:0, i15:0, a15:0, i16:0, a16:0, i17:0, a17:0,
(Kourtev et al. 2002; Waldrop et al. 2000)
10Me 17:0, i18:0
Gram-negative bacteria
12:0, 14:0, , 15:0 3OH, i15:0 3OH, 15:0 2OH, 16:1
(Kourtev et al. 2002; Waldrop et al. 2000)
2OH, i17:0 3OH, 17:0, 17:1ω8с, cy17:0, 18:1ω5с,
18:1ω7с, i18:1 H, cy19:0ω8с
Mycorrhizal
16:1ω5, 16:1ω5c, 18:2ω6c, 18:2ω6c, 18:2ω9c
Sulfate-reducing bacteria
10Me16:0, i17:1ω7c, 17:1ω6c
Methane-oxidizing bacteria
16:1ω8c,
16:1ω8t,
(Balser and Firestone 2005; Hinojosa et al. 2005)
(Kourtev et al. 2002)
16:1ω5с,
18:1ω8c,
18:1ω8t,
(Hill et al. 2000)
18:1ω6c
Aerobes
16:1ω7t, 16:1ω7c
(Hill et al. 2000)
Anaerobes
cy19:0 cy17:0
(Hill et al. 2000)
Protozoa
20:2ω6,9,c, 20:3ω6,9,12c, 20:4ω6,9,12,15c
(Kourtev et al. 2002)
Desulfosporomusa polytropa gen
14:1ω5с
(Sass et al. 2004)
Arthropoda
20:1ω9
(Haubert et al. 2008)
Table 2. Productive characteristics of seven new Chinese hybrid rice cultivars
Productive characteristics
Hybrid rice cultivars
Yield (kg ha-1)
Grain number per spike
Seed setting rate (%)
Plant height (cm)
IIyouming86
145.17± 8.38 ab
79.96±4.62 ab
123±7.10 a
8000.85±462.00 b
IIyouhang1hao
141.03± 8.14 ab
75.23±4.34 ab
125±7.22 a
7900.80±456.15 b
IIyouhang2hao
143.14± 8.26 ab
74.72±4.31 ab
122±7.04 a
7802.55±450.45 bc
XinyouHK02
128.22± 7.40 b
70.48±4.07 b
130±7.51 a
7748.25±447.30 bc
YiyouHK02
125.50± 7.25 b
72.71±4.20 ab
125±7.22 a
7564.50±436.65 c
Chuanyou167
172.78± 9.98 a
92.70±5.35 a
112±6.47 b
8609.40±496.95 a
44you167
180.71±10.43 a
94.88±5.48 a
110±6.35 b
8948.40±516.60 a
*The data in the table represented means, different letters in a column indicated significant difference among rice cultivars（LSD，P<0.05）
Table 3. PLFAs detected in rhizosphere of seven new Chinese hybrid rice cultivars
PLFAs*
12:0
14:0
Contents of PLFAs in rhizosphere of hybrid rice (µg g-1)
Ⅱyouming86
34.10±1.97 c
Ⅱyouhang1hao
Ⅱyouhang2hao
46.83±2.70 b
54.02±3.11 b
XinyouHK02
26.71±1.54 c
119.67±6.91 a
0.00±0.00 c
0.00±0.00 c
i14:0
31.63±1.83 c
42.36±2.45 bc
54.15±3.13 b
40.33±2.33
a14:0
30.25±1.75 c
60.77±3.51 b
59.99±3.46 b
59.60±3.44 b
67.85±3.92 b
15:0 2OH
25.65±2.57 a
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
15:0 3OH
57.46±3.32 b
61.91±3.57 b
71.35±4.12 b
51.70±2.98 b
0.00±0.00 c
48.48±2.80 b
355.54±20.53 a
29.80±1.72 c
32.05±1.85 c
32.45±1.87 c
38.95±2.25 c
0.00±0.00 d
110.44±6.38 b
211.03±12.1
8
a
26.77±1.55 b
9
b
c
0.00±0.00 c
46.40±2.68
b
c
107.82±6.23
b
0.00±0.00 c
c
116.04±6.70 b
46.82±2.70 b
44you167
100.18±5.78 bc
15:1 ISO G
96.37±5.56
35.39±2.04 c
Chuanyou167
82.80±4.78 c
14:1ω5с
121.68±7.03 b
b
YiyouHK02
c
0.00±0.00 c
46.03±2.66
49.27±2.84
b
c
b
c
412.03±23.79 a
90.39±5.22 a
153.74±8.88 a
274.40±15.84 a
Contents of PLFAs in rhizosphere of hybrid rice (µg g-1)
PLFAs*
i15:0
i15:0 3OH
a15:0
16:0
16:0 N
ALCOHOL
i16:0
a16:0
10Me16:0
Ⅱyouming86
298.14±17.2
7a
1
0.00±0.00 b
153.50±8.86 c
830.64±47.9
6
b
42.52±2.45 e
142.42±8.22 b
309.14±17.8
5
232.16±13.4
0
b
b
306.80±17.71 a
0.00±0.00 b
0.00±0.00 b
215.53±12.4
4
967.73±55.8
7
186.12±10.7
5
251.58±14.5
3
9
30.71±1.77
16:1 2OH
61.76±3.57 d
0.00±0.00 c
c
d
ab
b
104.83±6.05 cd
188.65±10.8
16:1ω9с
bc
61.10±3.53 de
c
149.62±8.64
36.27±2.09
b
b
bc
b
90.70±5.24 c
180.65±10.43 b
143.66±8.29 b
95.03±5.49 cd
148.98±8.60 bc
98.43±5.68
182.18±10.5
2
158.71±9.16
c
d
b
b
c
336.72±19.4
4
81.51±4.71
214.24±12.37 b
1108.86±64.02 a
243.29±14.0
5
138.46±8.00
41.02±2.37
482.63±48.2
6
81.55±4.71
c
c
d
0
551.77±55.1
8
92.88±5.36
0.00±0.00 c
b
103.69±5.99 b
584.31±33.74 a
0.00±0.00 b
0.00±0.00 b
161.92±16.19 a
115.08±6.64 c
857.78±49.52 a
262.93±15.18 b
164.43±9.49 c
0.00±0.00 c
0.00±0.00 c
352.76±20.37 b
b
673.05±67.31 a
d
37.46±2.16 b
122.39±7.07 b
cd
bc
260.83±15.06 a
0.00±0.00 b
182.30±10.5
53.85±3.11
271.94±15.7
90.88±2.25 c
86.03±4.97 b
38.38±2.22 c
a
174.85±10.10 a
0.00±0.00 b
50.87±2.94 bc
3
c
118.47±6.84 b
60.32±3.48 b
559.92±32.3
b
660.11±38.11 a
74.09±4.28
69.00±3.98
0.00±0.00 c
c
65.60±3.79 c
46.76±2.70 c
0
e
b
44.70±2.58 d
74.38±4.29 b
bc
d
54.98±3.17 a
60.93±3.52 bc
0.00±0.00 c
b
130.23±7.52 c
46.07±2.66
5
d
0.00±0.00 c
221.75±12.8
b
634.49±36.63 a
30.51±1.76 d
c
a
86.74±5.01 d
58.40±3.37 c
179.34±10.3
c
968.33±96.83
143.21±8.27 c
36.71±2.12 d
42.75±2.47 c
917.53±91.75 b
1043.14±60.23 a
782.76±45.19 a
139.04±8.03 b
10Me 17:0
c
c
166.18±16.62 a
164.40±9.49 b
2
114.34±6.60 c
c
b
0.00±0.00 d
b
187.41±10.8
126.98±7.33 bc
b
0.00±0.00 b
44you167
258.34±14.92 a
130.30±7.52 bc
55.09±3.18
b
199.55±11.52
38.37±2.22 b
56.95±3.29 cd
282.18±16.29
a
90.10±5.20 c
95.26±5.50 c
cy17:0
)
7
Chuanyou167
b
0.00±0.00 c
0.00±0.00 b
18:3ω6с(6,9,12
6
50.36±2.91
122.68±7.08 b
18:1ω9с
1c
37.85±2.18 e
0.00±0.00 b
18:1ω7с
248.69±14.3
129.53±7.48 b
286.98±16.57 b
0.00±0.00 b
190.77±11.0 b
815.26±47.0
a
64.08±3.70 d
104.03±6.01 b
18:1ω5с
a
0.00±0.00 b
6
138.35±7.99 b
d
i17:0
18:0
4
c
44.32±2.56 b
89.06±5.14 b
17:1ω8с
1088.41±62.8
5
YiyouHK02
302.35±17.4
27.14±1.57 d
43.26±2.50 d
a17:0
212.20±12.25 bc
XinyouHK02
236.47±13.6
43.19±2.49 bc
17:0
i17:0 3OH
Ⅱyouhang2hao
a
b
16:1ω5с
16:1 ISO G
Ⅱyouhang1hao
241.94±13.9 b
228.82±13.2
1
444.78±44.4
8
d
c
118.57±6.84 b
73.11±4.22 d
3
b
c
d
b
c
b
c
220.81±12.7 b
5c
0.00±0.00 c
296.56±17.1 b
2c
457.36±45.7
4
112.69±6.51
c
b
c
41.06±2.37
60.79±3.51
46.08±2.66
201.51±11.63
2465.77±246.5
8
297.92±17.20
c
c
d
b
c
b
c
b
c
a
b
c
540.40±54.04 b
109.04±6.30
b
c
243.56±14.06 a
214.20±12.37 a
324.02±18.71 a
236.09±13.63 a
875.16±50.53 a
1149.82±114.9
8
b
0.00±0.00 e
0.00±0.00 d
420.61±24.28 a
i18:0
0.00±0.00 c
0.00±0.00 c
0.00±0.00 c
0.00±0.00 c
36.69±3.67 b
29.44±2.94 b
111.90±11.19 a
i18:1 H
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
106.65±10..67 a
143.08±8.26 bc
187.88±10.85 b
97.52±5.63 c
112.08±6.47 c
604.80±34.92 a
40.82±2.36 cd
48.40±2.79 c
28.97±1.67 d
10Me18:0
11Me 18:1ω7с
141.08±8.15 c
244.74±14.1
3
a
10
141.94±8.19
b
c
51.77±2.99 c
40.99±2.37
c
d
116.44±6.72 b
Contents of PLFAs in rhizosphere of hybrid rice (µg g-1)
PLFAs*
cy19:0ω8с
20:0
20:1ω9с
20:4ω6,9,12,15
с
Total
Ⅱyouming86
221.33±12.7
8
98.54±5.69
c
c
d
0.00±0.00 b
85.39±4.93
5241.28
b
c
Ⅱyouhang1hao
274.94±15.8
7
c
114.26±6.60 bc
34.12±3.41 a
93.13±5.38 b
5128.84
Ⅱyouhang2hao
248.08±14.32 c
XinyouHK02
182.55±10.5
4
c
YiyouHK02
238.23±13.7
5
c
Chuanyou167
825.61±47.67 b
c
1062.93±61.37 a
130.58±7.54 b
74.53±4.30 d
75.54±4.36 d
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
0.00±0.00 b
64.69±3.73 d
60.99±3.52 d
186.26±10.75 a
4363.19
7776.22
77.28±4.46
bc
68.50±3.95
d
5573.04
4039.03
c
d
90.70±5.24
44you167
d
304.19±17.56 a
15134.74
*The data in the table represented means, different letters in a row indicated significant difference among soils of rice cultivars（LSD，P<0.05）
Fig.1. Principal component analysis of individual PLFA
11
Fig.2. The microbial community structure in rhizosphere of seven hybrid rice cultivars by using 16:0, 18:1ω9с and 10Me l7:0 as measures of
biomasses for bacteria, fungi and actinomycetes, respectively.
b
a
Lance-William distance
Lance-William distance
Fig.4. Cluster analysis of seven new Chinese hybrid rice cultivars based on productive characteristics (a) and PLFAs (b) by using
unweighted pair-group mean average (UPGMA) method
12