By
Kelompok 9 :
Agatha Maturbongs : 12/337941/PBI/1048
Nurhening Yuni Ekowati : 12/338474/PBI/1069
Plants as sessile organisms are exposed
persistently changing stress factors. Primary
stress such as drought, salinity, cold and hot
temperatures and chemicals are interconnected
in their effect on plants.These factors cause
damaged to the plant cell and lead to
secondary stresses such as osmotic and
oxidative stresses. Plants adapt
morphologically and physiologically and
biochemically
Active plants growth
in mesophile
organisms is 10-40oC.
Any temperature
which is under and
below that range
creates heat stress on
metabolic activities of
plants.
High temperature
morpho-anatomical,
physiological and
biochemical changes
in plants
Plants growth and
development
Reduction in economic
yield
Heat stress response is a reaction when tissues and cells of an
organism were exposed to sudden heat stress.
HS response is initiated by the activation of heat shock factors
(HSF) which cause expression of heat shock gene to
synthesis heat shock proteins
Heat shock proteins (HSPs) are spesific protein that are made
when cells are briefly exposed to temperature above their
normal growth temperature.
Heat stress respon and HSPs are highly conserved in every
organism.
HSPs can also be induced other stressor such as oxidants,
toxins, heavy metals, free radicals, and viruses, so they are
sometimes called the “stress protein”
Most heat shock proteins are chaperon, they
protecting plants againt stress by reestablishing
normal conformation and thus cellular
homeostasis.
HSF is a regulator in HSPs synthesis.
These proteins are grouped in plants into five classes
according to their approximate molecular weight :
(1) Hsp100
(2) Hsp90
(3) Hsp70
(4) Hsp60
(5) sHsps
Arabidopsis, the genetic
model for studying and
manipulating the heat
stress response.
Transgenic
overexpression
of Arabidopsis
thaliana heat shock
transcription factor
(HSF) results in a
synthesis of HSPs at
normal temperature
and significantly
increased basal
thermotolerance.
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Plants and animals share similar mechanisms
in the heat shock (HS) response, such as
synthesis of the conserved HS proteins (Hsps).
In general they require unique features to cope
with heat stress.
Hsa32 is a conserved HS-inducible gene in land
plants
The gene responds to HS at the transcriptional
level in moss (Physcomitrella patens),
Arabidopsis (Arabidopsis thaliana), and rice
(Oryza sativa).
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Hsa32 Is a Conserved HSInducible Gene in Land
Plants
Hsa32 Protein Is
Synthesized in Response to
HS
Charng et al, 2006
Wang et al, 2004
Wang et al, 2004
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Al-wahibi, M. H. 2010. Plant heat-shock protein : a mini review. Journal of
King Sau University xxx: xxx-xxx
Baniwal, S. K, K. Bharti1, K. Y. Chan, M. Fauth, A. Ganguli, S. Kotak, S.
K. Mishra, L. Nover, M. Port, K. Scharf, J. Tripp, C. Weber, D. Zielinski
and P. V. Koskull-döring. 2004. Heat stress response in plants: a complex
game with chaperones and more than twenty heat stress transcription
factors. J. Biosci. 29(4) : 471-487
Charng, Yee-yung, Hsiang-chin Liu, Nai-yu Liu, Fu-chiun Hsu, and
Swee-suak Ko. 2006. Arabidopsis Hsa32, a Novel Heat Shock Protein, Is
Essential for Acquired Thermotolerance during Long Recovery after
Acclimation. Plant Physiology, Vol. 140, pp. 1297–1305
Wahid, A., S. Gelani, M. Ashraf, M.R. Foolad. 2007. heat tolerance in
plants : an Overview. Environmental and experimental Botany 61 : 199223
Wang, Wangxia, Basia Vinocur, Oded Shoseyov and Arie Altman. 2004.
Role of plant heat-shock proteins and molecular chaperones in the abiotic
stress response. TRENDS in Plant Science Vol.9 No.5.
SEKIAN
DAN
TERIMA KASIH
1.
2.
Bagaimana hubungan antara rusaknya perikarp pada buah tomat?
bagaimana kaitannya dengan glisin betain?
jawab : kerusakan perikarp pada buah tomat disebabkan oleh
adanya cekaman panas yang merusak membran sel. Panas
menyebabkan perubahan integritas dan fluiditas membran, serta
menyebabkan enzim-enzim yang terdapat di dalam sel
terdenaturasi sehingga sel menjadi mati. Selain itu dengan adanya
cekaman panas menyebabkan sintesis likopen terganggu dan
bahkan tidak terjadi, kemungkinan karena enzim yang terlibat
dalam sintesis likopen mengalami denaturasi.
sedangkan glisin betain merupakan salah satu protein
osmoprotektan , peningkatan konsentrasi glisin betain dalam
cekaman panas adalah untuk menjaga homeostasis sel, yaitu dengan
menjaga tekanan osmosis di dalam sel.
Bagaimana kaitan Hsf yang dioverekspresikan pada tanaman?
Jawab : overekspresi Hsf pada tanaman menyebabkan tanaman
lebih toleran terhadap cekaman panas.
3.
4.
Apakah pada tumbuhan memiliki semua jenis
hsp?
Jawab: pada 1 jenis tumbuhan tidak memiliki
semua jenis hsp, masing-masing tumbuhan
memiliki hsp yang berbeda-beda tergantung
adaptasi dan stres yang dialaminya. Misalnya
Arabidopsis memiliki 18 gen yang mengkode
pembentukan Hsp70 dan Hsp90, Hsp100 dimiliki
oleh beberapa tanaman antara lain Arabidopsis,
kedelai tembakau, padi dan jagung.
Hsp di hasilkan di bagian mana saja pada
tumbuhan?
Jawab : Hsp dihasilkan pada berbagai organel sel,
misalnya Hsp70 dihasilkan pada sitosol,
kloroplas, dan mitokondria, sedangkan Hsp22
dihasilkan pada retikulum endoplasma.