BRASSINOSTEROIDS. Abiotic Stress Tolerance In Tomato And Wheat Plants

Transcription

1 BRASSINOSTEROIDS Abiotic Stress Tolerance In Tomato And Wheat Plants Qazi Fariduddin, Ph.D. Associate Professor Department of Botany, Faculty of Life Sciences Aligarh Muslim University, Aligarh, India

2 STRESSES External conditions that adversely affect growth, development, or productivity Stresses trigger a wide range of plant responses: - altered genes - expression in cellular metabolism - changes in growth rates and crop yields Biotic - caused by organisms Abiotic Due to an excess or deficit in the physical or chemical environment Biotic and abiotic stresses can reduce average plant productivity by 65% to 87%, depending on the crop type

3 Abiotic Stress Environmental conditions that can cause abiotic stress: water-logging drought high or low temperature excessive soil salinity inadequate mineral in the soil too much or less light Heavy metal toxicity

4 Plant-Environment Interactions Abiotic stress Biotic stress

5 Factors determining stress responses Type of stress Number of times the plant is subjected to stress Duration Severity Additional/synergistic effects of multiple stresses Genotype Developmental stage

6 Stress tolerance mechanisms Avoidance mechanisms prevents exposure to stress Tolerance mechanisms permit the plant to withstand stress Acclimation alter their physiology in response to stress

7 Stress tolerance

8 Predicting Life Processes: Reverse Engineering Living Systems DNA (storage) External stimuli Transcription Translation Proteins Biochemical Circuitry Phenotypes (Traits) Gene Expression Proteomics Metabolomics

9 APPROACHES FOR AMELIORATION OF PLANT STRESSES Abscisic acid (ABA) Ethylene Jasmonic acid (JA) Salicylic Acid (SA) Calcium Our approach Brassinosteroids (BRs)

10 O c c u r r e n c e & D i s t r i b u t i o n o f B R s 69 Brassinosteroids (65 unconjugated and 5 conjugated) have been isolated from 64 plant species Angiosperms Gymnosperms Pteridophyte Bryophyte Chlorophyte 12 Monocotyledons 41 Dicotyledons 6 Conifers Equisetum arvense Marchantia polymorpha Hydrodictyon reticulatum

11 A C T I V E A N A L O G U E S O F B R S 24-Epibrssinolide Brssinolide 28-Homobrssinolide T h e p r e s e n c e o f s a t u r a t e d a l k y l ( C H 3 o r C 2 H 5 ) a t p o s i t i o n C a n d a m e t h y l a t C m a k e s B R s b i o l o g i c a l l y m o r e a c t i v e. M o s t o f B R s c a r r y S - o r i e n t e d a l k y l g r o u p a t C A l t h o u g h, t h e r e a r e e x c e p t i o n s a m o n g B R s w i t h R - o r i e n t e d a l k y l ( e. g E B L a n d e p i C S ).

12 R O L E O F B R A S S I N O S T E R O I D S ( B R S ) Polyhydroxy steroidal plant hormone Cell elongation Cell expansion Vascular differentiation Seed germination Vegetative growth Apical dominance, reproduction and senescence Modulation of stress responses

13 BRASSINOSTEROIDS Abiotic Stress (Bajguz and Hayat 2009) Saline stress Water stress Heavy metal stress Temperature stress Biotic Stress (Bajguz and Hayat 2009) Bacterial Fungal Viral pathogens Pesticides

14 Cumulative effect of two abiotic stresses

15 Experimental Crops Tomato (Lycopersicon esculentum) Wheat (Triticum aestivum) Abiotic stresses Low temperature stress (Climate change) Combination of salt and metal stress

16 Loss of yield in tomato by low temperature stress

17 To improve the Objective tolerance ability of tomato plant against low temperature st ress by c ommiss ioning bras sinos teroids f or s ustainable agric ult ure prac tices

18 Low temperature tolerance mechanism Fariduddin et al., 2017; Envron Sci Pollu Res

19 Experimental Layout Transplanted seedlings At 20 DAT plants were exposed at different day/night temperatures for 24 hours 10/3 0 C 12/7 0 C 20/14 0 C 25/18 0 C Nursery Sterilized with 0.01% HgCl 2 solution 30 DAT foliar treatment of DDW (control) or 10-8 M of HBL or EBL Seeds of Lycopersicon esculentum Sampled at 40 DAT

20 PARAMETERS STUDIED Growth Biomarkers Physiological Traits Chlorophyll content (SPAD level) Gas exchange parameters Maximum Quantum yield of PSII Stress Biomarkers Leaf electrolyte leakage Leaf proline content Biochemical parameters Leaf nitrate reductase activity Leaf carbonic anhydrase activity Leaf catalase activity Leaf peroxidase activity Leaf superoxide dismutase activity Yield Attributes Number of fruits plant -1 Fruits yield plant -1 Lycopene content in fruit

21 Growth biomarkers

22 Photosynthetic attributes

23 Biochemical parameters

24 Antioxidant defense system

25 Yield attributes

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27 Conclusions Exposure to varied low temperatures in two contrasting tomato varieties resulted in adaptive responses. Response of the cultivars to BRs was better in S-22 than PKM-1. S-22 accumulated higher content of lycopene than PKM-1. Out of the two analogues of BR tested against a range of low temperature stress in tomato plants, EBL emerged as more effective than HBL EBL treatment was more effective for yield and quality improvement of tomato cultivars under low temperature stress.

28 Response of wheat to brassinosteroids under combined stresses of aluminum and salt

29 Objectives To assess the impact of combined Aluminium and salt stress on wheat To explore the best suited mode of application of brassinosteroids (BRs) analogues under combined stresses (Al and Salt stress) To examine the role BRs on the enzymes of proline metabolism under combined stress of aluminium and salt To study the involvement of BRs in regulating the antioxidant system under these stresses To dissect the expression of proteins in wheat under aluminium and salt stress in the presence and absence of BRs Salt Stress & Al Stress BRs Salt Stress + Al Stress

30 Experimental Layout Seeds of seven different verities of wheat were sown in sand culture DBW LOK DBW- 17 LOK All these varieties treated with different levels of Al (5.0, or 10.0 mm) and/or NaCl (100, or 150 mm) for successive 3 days at 10 day stage of growth Tolerant and sensitive varieties were selected

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35 Experimental Layout These two varieties selected on the basis of previous experiment Salt-tolerant Salt-sensitive LOK-1 LOK-1 LOK-1 LOK Seed soaking treatment of EBL was given before sowing for 8 hours and at 10 days of growth, seedlings were exposed to 10 mm of Al and/or 150 mm of NaCl At 25 days of growth, plants were given foliar treatment of 10-8 M of EBL for 5 days LOK-1 LOK-1 LOK-1 LOK Harvested at 45 days stage of growth

36 Effect of EBL on the NaCl and/or Al induced changes in wheat

37 Effect of EBL on the NaCl and/or Al induced changes in wheat

38 Proline biosynthesis

39 Effect of EBL on the NaCl and/or Al induced changes on P5CS activity, Delta-OAT activity and proline content in wheat.

40 Antioxidant Enzymes

41 Proteome determines the cellular phenotype and its plasticity in response to external signals. It is proteins that are directly involved in both normal and stress-associated biochemical processes. Availability of genomic sequence Power of 2-DE Progress in chromatographic techniques for the separation of complex mixture of proteins Advances in MS Development of computational methods

42 Plant Material Protein extraction, resolution and digestion Control Stress condition Protein extraction and sample preparation + 4 ph 7 - Isoelectric focusing (1 st Dimension) + 4 ph 7 - Reduction and alkylation SDS-PAGE (2 nd Dimension), Visualization (Coomassie BB/Silver staining) (kda) M 4 ph 7 (kda) M 4 ph Over-expressed induced absent under-expressed Spot numbering (1, 2, 3.x), excision and digestion Protein identification HPLC/Mass spectrometry and protein identification LS-MS peptide-mass fingerprint spectrum of the tryptic digest of differential protein and its idenification on MASCOT

43 Global proteome profile in wheat

44 Protein spots were excised MALFI-TOF-TOF analysis Identification using the database search program MASCOT (Matrix Science) software against the NCBInr/Swiss-Prot database taking green plants, as taxonomy. Function analysis by UniProt database

45 Identification of differentially expressed proteins Entry name Protein identification Matched peptides Sequence coverage Nominal M r NCBI accession no. MASCOT score Calculated pi Location Function Cellular distribution

46 Schematic model of action of EBL on the induction of combine stress of aluminium and salt in wheat plants

47 Conclusions Our results provide a novel, global insight into the mechanism of EBL influence on combination of Al and salt tolerance in plants. Metabolic pathways that are shared and curtailed under variable overlap of stress regimes up-expressing the protein regulators will help to unravel further insight for understanding the molecular hierarchy of stress signalling. In addition to this, lots of information gathered via proteomic approach could be used to establish multi-stress tolerant varieties of crop plants.

48 Acknowledgements & Funding RESEARCH GROUP Dr. Mohammad Yusuf Faculty, Biology Department United Arab Emirates University Al Ain, Abu Dhabi, UAE Dr. Mohd Tanveer A Khan Postdoctoral fellow College of life science and technology Huazhang Agricultural University Hubei, Wuhan, CHINA Dr. Bilal Ahmad Mir Biology Teacher Department of School Education Jammu and Kashmir, INDIA Faroza Nazir PhD Student Aligarh Muslim University Aligarh, INDIA Anjuman Hussain PhD Student Aligarh Muslim University Aligarh, INDIA

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