Change of β-Amylase Activity In Germination and Early Rice seedlings
Under Hypoxic and Anoxic Water
Ji-Young
1
Shon ,
1
Kim ,
1
Lee ,
1
Ko ,
1
Kim ,
1
Yang ,
Joonhwan
Chung-Keun
Jong-Cheol
Bo-keong
Woon-ho
1
1
1
2
Won-Ha Yang , Chung-Kon Kim , Yeon-Gyu Kim and Nam-Jin Chung
(1)Rice Research Division, National Institute of Crop Science, RDA, Suwon, South Korea
(2)Department of Crop Science and Biotechnology, Chonbuk National University, Jeonju, South Korea
Abstract
Direct seeded rice, especially water seeding, requires strong hypoxia tolerance for stable seedling establishment under submerged paddy. This study was carried out to understand relationship between anoxia tolerance and carbohydrates
catabolism in anoxic rice seedlings of japonica rice. Four rice cultivars were experimented as anoxic tolerant rice cultivars (cvs WD-3, PBR) and susceptible rice cultivars (cvs Juanbyeo:JA, Nampyeongbyeo:NP). The coleoptile elongation
and fresh weight were markedly supressed by anoxia than normoxia, however those of WD-3 and PBR was faster than JA and NP. Soluble sugar concentration of WD-3 and PBR (tol var.) was more increased than JA and NP (sus var.)
under anoxia. Especially maltose concentration of WD-3 and PBR (tol var.) increased up to 2-fold at 3 days after treatment and was retained until 9 days after treatment however that of JA and NP increased only 1.3-fold.
β-Amylase that cleaves maltose from starch, those activities of WD-3 and PBR were increased up to 10-fold at 9 days after treatment than before treatment. Otherwise α-amylase activity of WD-3 and PBR was rapidly decreased after
treatment. These results suggest that β-amylase activity strongly associate with degradation of sugar from starch in endosperm during germination stage and its product as maltose support elongation of rice coleoptiles in anoxia.
3%, Direct-seeding
 To find japonica rice germplasm having hypoxic and
anoxic tolerance adabtable environment of south Korea
 To investigate the physio-biochemical characteristics of
hypoxic and anoxic tolerance of rice germination and early
seedlings
4
3
2
1
3
6
9
Media
Oxygen
Temp
Light
Moisturized Ambient air 18±4℃
12/12h
(phytotron) (light/dark)
Hypoxia-submerged DW
7-9ppm
3.0
Hypoxia
Air
Air
12
8
2
4
6
8
2
0
3
6
9
Anoxia
Strach degradation
4
6
0
3
 4 Rice varieties were tested:
Anoxic tolerant Var; WD-3 and PBR (weedy rice collected from Korea)
Anoxic intolerant Var: Juan byeo (JA)and Nampyeonbyeo(NP)
References
Shon, J. 2011. Ph.D thesis. Chonbuk National University.
Zhang, H., et al. 2005. Planta 220: 708-716
Yoon, B. 2002. Korean J. Crop Science 33(3):162-166
Magneshi, L., Kudahettige, R., Alpi, A. & Perata, P. 2009.
Plant Biology 11:561-573
Soluble sugars (%)
Phytotron chamber
Air
24
JA
NP
WD3
PBR
Hypoxia
28
26
24
22
22
8
20
20
18
18
Anoxia
24
22
20
18
0
10
9
3
6
AirDays after treatment
0
9
JA10
NP
WD39
PBR
3
6
9
Hypoxia
Days after treatment 10
0
3
6
Anoxia
Days after treatment
9
Discussion
9
Increment of β-amylase activity may
contribute to elongation of rice early
7
7
7
seedlings at submerged anoxic condition.
6
6
6
Expression of BAMY1 at rice early
5
5
5
0
3
6
9
0
3
6
9
0
3
6
9
seedling stage proved that β-amylase
Days after treatment
Days after treatment
Days after treatment
was synthesized de-novo.
Fig 2. Soluble sugar and maltose concentration in rice seedlings of 4 Maltose play an important role in rice
cultivars that were treated with air, hypoxia and anoxia at 0, 3, 6 and 9 anoxic seedlings that provide energy
days atert treatment.
source as well as carbon building block of
cell wall and may control cell osmosis,
8
8
9
0
3
6
9
Days after treatment
Fig 4. Differential expression of transcripts of
genes related with starch degradation
metabolism in WD-3(WD3) and Juanbyeo(JA).
The normalized data were hierachically
clustered using average linkage on Euclidean
distance.
Fig 1. Coleoptile elongation behavior of 4 rice cultivars under air,
hypoxia and anoxia. (A: WD-3, B: Juan)
30
6
Days after treatment
Days after treatment
Days after treatment
Days after treatment
Anoxia
0.0
8
9
2
4
0.5
6
6
4
1.0
4
3
6
JA
NP
WD3
PBR
JA
NP
WD3
PBR
1.5
Maltose (%)
Anoxic treatment
16
2.5
2.0
0
Fig 3. α-Amylase activity and β-Amylase activity in rice seedlings of 4 cultivars that
were treated with air, hypoxia and anoxia at 0, 3, 6 and 9 days atert treatment.
Anoxia
Hypoxia
2
<1 ppm
Hypoxia
9
Hypoxia
0
Anoxia
6
8
Days after treatment
Air
3
Days after treatment
Air
(U mg-1 protein)
¥â-amylase activity
B
Days after treatment
0.1%agar
0
Days after treatment
0
Coleoptile length (cm)
 Method for normxia, hypoxia and anoxia treatment on germinated rice
Normoxic, Hypoxic,
5
0
Results
Materials & Methods
Anoxia-submerged
JA
NP
WD3
PBR
0
97%, Machine-transplanting
A
Anoxia
Hypoxia
Air
6
20
 Although direct seeding method has advantages of
lavor and time saving, it was not widely distributed.
Unstable seedling establishment, lodging and sprouting of
weedy rice are the reason why direct-seeding method
cannot widely distributed in South Korea.
Treatment
Normoxia (Air)
(U mg-1 protein)
 Rice cultivation method of South Korea
¥á-amylase activity
Objective
Background
Machine transplanting culture
for semi-adult Seedlings
7
8
JiYoung Shon: olive1001@korea.kr