[農(nóng)學]高級植物逆境生理

1、植物逆境生理與分子遺傳學植物逆境生理與分子遺傳學慕自新慕自新生命科學學院研究植物逆境生理的意義研究植物逆境生理的意義 全球性生態(tài)環(huán)境日漸惡化，自然災害嚴重的影響全球性生態(tài)環(huán)境日漸惡化，自然災害嚴重的影響植物正常的生長發(fā)育，影響了農(nóng)業(yè)生產(chǎn)和人類的社會植物正常的生長發(fā)育，影響了農(nóng)業(yè)生產(chǎn)和人類的社會生活。生活。 研究植物逆境下的生理反應，弄清植物抗逆性的研究植物逆境下的生理反應，弄清植物抗逆性的本質(zhì)并加以調(diào)控，有助于培育和栽培具有特殊適應能本質(zhì)并加以調(diào)控，有助于培育和栽培具有特殊適應能力的作物，減少災害引起的經(jīng)濟損失，提高農(nóng)業(yè)豐產(chǎn)，力的作物，減少災害引起的經(jīng)濟損失，提高農(nóng)業(yè)豐產(chǎn)，改善人類的社會生活。

2、改善人類的社會生活。植物逆境生理概論植物逆境生理概論 本課程以植物響應非生物環(huán)境脅迫為主，研討抗逆高效農(nóng)業(yè)的生理學基礎、植物耐逆性的調(diào)控及信號轉導、植物響應逆境的相關基因及其調(diào)控、提高植物耐逆性的轉基因技術以及植物對逆境整體響應的生理學機制等專題。陸生植物的特殊性陸生植物的特殊性l陸生植物的水源性l不可移動性l穩(wěn)態(tài) （水、離子、電解質(zhì)、氧化還原狀態(tài)）l細胞中生命活動的高度區(qū)格化Certain functions of plant membrane systems研究內(nèi)容研究內(nèi)容l植物逆境生理概論（4學時）l干旱(6學時)l冷害、凍害（6學時）l鹽脅迫（6學時）l營養(yǎng)脅迫（6學時）lABA信號轉

3、導（6學時）l氧化脅迫(ROS代謝) （6學時）l其它(CO2脅迫UV、O3)研究內(nèi)容研究內(nèi)容lStress Perception and Signal TransductionlStress Regulation of Gene ExpressionlPhysiology and Metabolism ion homeostasis, regulation of osmolyte synthesis and accumulation, water balance and stomatal movements.lConquering Stress breeding, transgenics,

4、and the identification of markers associated with abiotic stresses幾個植物生物學方面的重要雜志lAnnual of Plant BiologylTrends in Plant sciencelCurrent Opinion in Plant BiologylPlant CelllPlant Journal (Blank well)lPlant PhysiologyllSciencelNatureScience Direct經(jīng)典文獻lBoyer,JS(1982).Plant Productivity and environment

5、. Science, 218:443-448lZhu, JK(2002). Salt and draught stress signal transduction in Plants. Annu.Rev.Plant Biol. 53: 247-273lYamaguchi-Shinozaki K, Shinozaki K. RANSCRIPTIONAL REGULATORY NETWORKS IN CELLULAR RESPONSES AND TOLERANCE TO DEHYDRATION AND COLD STRESSES. Annu.Rev.Plant Biol, 2006, 57: 78

6、1-803 lRao KVM, Raghavendra AS and Reddy KJ eds. Physiology and Molecular Biology of Stress Tolerance in Plants.Springer, 2006lTae-Houn Kim, Maik Bohmer, Honghong Hu, Noriyuki Nishimura, and Julian I. Schroeder. 2010. Guard Cell Signal Transduction Network: Advances in Understanding Abscisic Acid, C

7、O2, and Ca2+ Signaling. Annu. Rev. Plant. Biol. 61: 561-591 lTakashi Hirayama and Kazuo Shinozaki. Research on plant abiotic stress responses in the post-genome era: past, present and future. The Plant Journal (2010) 61, 10411052lBlackwell Plant Science lScience Direct lHighWire Press lSpringer著名數(shù)據(jù)庫

8、著名科學家網(wǎng)站著名科學家網(wǎng)站l/jkzhu/lhttp:/labs.psc.riken.jp/gdrt/English/index.htmll/faculty/schroeder.htmll/lhttp:/ JKJulian Plant response to abiotic stressfrom genes to the whole plantPromotional paragraph “In the next 50 years, mankind will con

9、sume as much food as we have consumed since the beginning of agriculture 10,000 years ago” - Clive James “And he gave it for his opinion, that whoever could make two ears of corn or two blades of grass to grow upon a spot of ground where only one grew before, would deserve better of mankind, and do

10、more essential service to his country, than the whole race of politicians put together.” Jonathan Swift “Gullivers Travels” (1726) l植物頻繁地面臨脅迫,即那些對植物生長發(fā)育或繁殖產(chǎn)生不利影響的外部條件.l脅迫可以是生物性的,即由其他生物所施加,或者是非生物性的,即由過度或不足的物理或化學條件引發(fā).l對脅迫的抗性或敏感性是由植物的種類、基因型以及所處的發(fā)育階段決定的.l脅迫可以引發(fā)植物的一系列反應,從調(diào)節(jié)基因表達和細胞代謝到生長速率和作物產(chǎn)量的變化.l脅迫的持續(xù)時間

11、、嚴重性以及出現(xiàn)的頻率都可以影響植物的反應.l多種不利條件聯(lián)合作用會引起與單種類型的脅迫出現(xiàn)時不同的反應.l植物對脅迫的反應可能由脅迫直接引起,也可能由脅迫誘導的損傷所引發(fā),如膜完整性的破壞.脅迫特征脅迫特征植物特征植物特征反應反應結果結果l植物的抗脅迫機制可以分為兩大類: 逃避逃避(avoidance)機制,即防止接觸脅迫,和耐受耐受(tolerance)機制,即使植物可以抵抗脅迫.l適應適應（adaptation）,即經(jīng)進化而提高一個生物種群對環(huán)境的適應度, 是由基因型決定的組成型抗脅迫性狀, 不論植物是否處于脅迫中, 都會表達.如內(nèi)陷的氣孔,反射光的刺和深根系.順應順應（acclimat

12、ion）,即生物個體對環(huán)境因素改變作出的調(diào)節(jié)在順應過程中，一個生物個體改變它的體內(nèi)穩(wěn)態(tài)體內(nèi)穩(wěn)態(tài)（homeostasis）,即穩(wěn)態(tài)生理，來順應外部環(huán)境的轉變Two response modelsLevitt: avoidance/toleranceZhu: homeostasis/ protectionSome of the prominent abiotic stress tolerance mechanismsSome of the common plant responses to abiotic stressesThe path of stress tolerance in plants

13、Stress-induced morphogenicresponses: growing out of trouble?Plants exposed to sub-lethal abiotic stress conditions exhibit a broad range of morphogenic responses. Despitethe diversity of phenotypes, a generic stress-inducedmorphogenic response can be recognized that appearsto be carefully orchestrat

14、ed and comprises three components:Trends in Plant Science, 2007, 12: 98-105, (a)inhibition of cell elongation,(b) localized stimulation of cell division and (c)alterations in cell differentiation status. It is hypothesized that the similarities in the morphogenic responses induced by distinct stress

15、es, reflect common molecular processes such as increased ROS-production and altered phytohormone transport and/or metabolism. The stress-induced morphogenic response (SIMR) is postulated to be part of a general acclimation strategy, whereby plant growth is redirected to diminish stress exposure.(ac)

16、 SIMR stress-induced changes in root and/or shoot morphology.Shoot development of 21-day-old Arabidopsis thaliana raised on (a) 0, (b) 30 and (c) 50 mM Cu. Note equal numbers of newly formed leaves despite a strong inhibition of leaf expansion. Scale bars in (ac) = 1 mm;1. SIMR: a common, whole plan

17、t response to abiotic stress1. 1 Heavy metals induce morphogenic responses(dh) Development of the root apical zone of 7-day-old Arabidopsis, raised on control medium (d,g), or medium supplemented with (e) 30 mM or (f,h) 50 mM Cu. The shorter distance between the root tip and the root hair zone is an

18、 indication of a faster differentiation process compare (d) and (f), and the increase in root hair density compare (g) and (h). The lower rim of (g) and (h) is spaced 45 mm from the root tip growth. Scale bars in (dh) = 200 mm;(i) Formation of lateral root primordia by an Arabidopsis seedling expose

19、d to ROS-producer alloxan (1 mM). Note excessive formation of lateral roots. Scale bar =1 mm; (j) Root development on an Arabidopsis seedling grown for 7 days on 0.6 mM tert-butyl hydrogen peroxide (a stable H2O2 derivative). Note excessive production of lateral roots. Scale bar = 200 mm. (k) Format

20、ion of multiple lateral roots by Arabidopsis seedlings treated with alloxan (1.5 mM). Note the short division or elongation zone, indicating fast differentiation of epidermis and cortex tissue, and excessive formation of lateral root primordia. Scale bar = 200 mm;1.2 Other root-stress-induced morpho

21、genic responses: nutrient-deficiencies and hypoxia(lm) Root architecture of Arabidopsis grown for 17 days on phosphate-deficient medium (1 mM) (l), or for 10 days on phosphate-enriched (1 mM) medium (m). Scale bars in (l,m) = 1 cm; (n) Root hair growth of Arabidopsis grown for 14 days under phosphat

22、e-deficient conditions (1 mM). Scale bar in (n) = 0.5 mm;1.3 UV-B-induced morphogenic responsesOverview of shoot-stress-induced morphogenic responsesSchematic presentation of the effects of abiotic stress on plant morphology(a) Overview of root-stress-induced morphogenic responses, including an inhi

23、bition of root elongation, blocked cell division in the primary meristem and increased formation of lateral roots ;(b) Overview of shoot-stress-induced morphogenic responses, including the inhibition of shoot elongation, increased formation of lateral shoots and increased leaf thickness向水性向水性2. Sign

24、als that mediate SIMRl2.1 Stress-induced alterations in auxin metabolisml2.2 ROS as signals for SIMRCd-induced changes in auxin distribution. Exposure of roots to heavy metals can induce SIMR, comprising a redistribution of growth. In this example the root system of 6-day-old Arabidopsis thaliana se

25、edlings was exposed to 50 mM cadmium for a period of 48 h. This leads to a redistribution of DR5-GUS expression, reflecting alterations in auxin re-distribution. Auxin levels near the root tip (RAM) are generally decreased following exposure to Cd, mirroring the cessation of cell-division. However,

26、auxin levels are increased in the root middleand upper zones, and this is found to coincide with the auxin-induceddevelopment of several lateral primordia. Scale bars = 800 mm (a) or 200 mm (b,c).Diagram indicating main regulatory interactions that control SIMR. Stress-induced morphogenic responses

27、involve changes in phytohormone and ROS-metabolism. (1) Chronic stress conditions directly impact on auxinhomeostasis via effects on auxin synthesis and distribution, or indirectly via changes in ROS metabolism. (2) Stress directly stimulates ROS-metabolism as an unavoidable consequence of cellular

28、disruption, or as part of a controlled oxidative burst. Auxins, via their effect on the cellular redox state, co-regulate ROS homeostasis.(3) Changes in auxin metabolism induce morphogenic alterations, including lateral root branching and sprouting of axillary buds. (4) ROS impact on morphogenesis v

29、ia effects on cell cycle activity (oxidative stress checkpoint), the microtubule network and the flexibility of the cell wall.上圖說明上圖說明3. Molecular responses underlying SIMR: cell wallflexibility, cell cycle progression and microtubuliThe molecular mechanisms underlying SIMR can becatalogued as proce

30、sses that are influenced by abioticstresses and simultaneously impact on morphogenesis.Because a SIMR comprises parallel inhibition of cellelongation and localized stimulation of cell division, theseprocesses are likely to function as focal points in its regulation. The cell cycle acts as a focal po

31、int for stress signals. The actions of phytohormones on the cell cycle, including accessory cyclins and cyclin-dependent kinases, have been detailed elsewhere . Cell cycle progression has been shown to be controlled directly by the oxidative stressor menadione(甲萘醌,Vitamin K), and an oxidative stress

32、 checkpoint has been postulated. The antioxidants ascorbate and glutathione interact with cell cycle progression as well3.1 Cell cycle progression3.3 Cell wall elongation The cell wall is a dynamic structure that plays an important role in controlling cell growth. The auxin mediated cellular elongat

33、ion response is thought to involve proton-mediated activation of expansins, which open the hydrogen bonding between cellulose microfibrils, causing the laminate structure of the cell wall to loosen. Once the rigidity of the wall has been reduced, cells can elongate. ROS and antioxidants contribute t

34、o this elongation response. Auxin promotes the production of superoxide radicals in the growth-controlling outer epidermis of maize coleoptiles(胚芽鞘 ) , and auxin-induced extension of roots can be mimicked using ROS3.2 Microtubuli Cellular extension is partially under the control of the microtubule n

35、etwork. Oxidative stressors and antioxidants, as well as auxins , can change the orientation of microtubules by activating specific MAP-kinases, resulting in altered microtubule and cell elongation dynamics and creating a link between oxidative stress and plant architecture. 酸生長假設酸生長假設-生長素誘導的質(zhì)子外排促進細

36、胞的伸展生長素誘導的質(zhì)子外排促進細胞的伸展 Expansins對細胞壁的松弛作用 Expansins 能夠削弱細胞壁多糖的非共價鍵結合Spatial distribution of elongation growth and ROS production in a maize leafDistribution of H2O2 in Arabidopsis root visualized by 3-(p-hydroxyphenyl) fluorescein (HPF)fluorescence. (a) Whole root tip; (b) lateral root with a part of

37、 the main root; (c) close-up on the differentiation zone. White arrows show the forming root hairs; mz, meristematic zone; ez, elongation zone; dz, differentiation zone, fdz, fully differentiated zone. Bars, (a,b)150 m, (c) 75 mH2DCFDANitroblue tetrazolium stains the growing tips of wild-type root h

38、airs soon after initiationrhd2 mutationDistribution of O2 visualized by nitroblue tetrazolium (NBT) staining in Arabidopsis root tip. Bar, 100 mEffect of treatments that modify apoplastic ROS concentration on the growth of maize leaf segments(treated 2 h)Hydrogen peroxide mediates plant root cell re

39、sponse to nutrient deprivationLocalization of ROS in Arabidopsis roots during K deprivationA,B: K-sufficient roots ; C,D: K-deficient roots; E,F: Negative control脅迫反應中植物基因的表達模式通常有所脅迫反應中植物基因的表達模式通常有所改變改變脅迫誘導的代謝變化和發(fā)育變化通常是由基因表達模式的改變造成的脅迫反應始于植物在細胞水平上對脅迫的識別這種識別可以激活信號轉導途徑，從而在個體細胞內(nèi)及整株植物中傳遞最終，發(fā)生于細胞水平上的基因表達變

40、化，由整株植物整合成一種反應，來改變植物的代謝和生長發(fā)育Bohnert HJ et al. Unraveling abiotic stress tolerance mechanisms getting genomics goingHomeostasis, a set-value for metabolism under optimalconditions, is rarely achieved by plants because of the costexerted by external stress factors: climatic, biotic, and nutrientimbala

41、nces. Among these, stresses caused by abioticconditions, such as temperature extremes (freezing, cold andheat), water availability (drought and ion excess) and iontoxicity (salinity and heavy metals), have been difficult todissect because defense responses to abiotic factors requireregulatory change

42、s to the activation of multiple genes andpathways.Current Opinion in Plant Biology 2006, 9:180188Genomics technologies that have emerged duringthe past decade have been useful in addressing, in anintegrated fashion, the multigenicity of the plant abioticstress response through genome sequences; cell-, organ-,tissue- and stress-specific transcript collections; transcript,protein and metabolite profiles and their dynamic changes;protein interactions; and mutant screens.Flow chart of stress systems biology. The chart connects the systems approach to the analysis of plant stress response pathw