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Additional file 8: Supplementary Figure 1. Variation in precipitation and relative humidity experienced by diverse rice panels evaluated in field trials 1–4. Trial 1(2017), Trial 2(2018), Trial 3(2011) and Trial 4 (2013).

Rice is the major staple food for one-third of the world’s population. Rice requires high amount of water as compared to other cereal crops. In this context, we screened traditional rice genotypes collected from RARS, Pattambi and Ambalavayal for drought tolerance. Based on the morpho-physiological characters, the plants which showed wilting symptoms were screened according to international standard i.e., IRRI leaf score 7.0. The genotype which showed no wilting symptom even after 90% of the plants were showing wilting was identified as tolerant and the plant which showed early wilting symptom was identified as susceptible genotype. The genotype Chuvanna Modan has taken 25 days and the genotype Parambuvattan has taken only 10 days for wilting. After 90% of plants reached IRRI score 7.0 phenotypic observations i.e., electrical conductivity, measurement of stomatal conductance and transpiration rate using Infra red gas analyser were recorded. Root traits were also measured. The identified tolerant and susceptible genotypes were further subjected to 2D gel electrophoresis to identify and characterize the differentially expressed proteins for drought tolerance. Totally four differentially expressed protein spots were identified in Chuvanna Modan. The differential protein spots were sequenced by Matrix Assisted Laser Desorption/Ionization–Time of Flight Mass Spectrometry (MALDI–TOF/MS). Spot 1 and 2 were identified as ribulose bisphosphate carboxylase small subunit, spot 3 was identified as Protein tyrosine phosphatases and spot 4 was identified as Photosystem II stability/assembly factor HCF136.

Drought is one of the major abiotic stresses which adversely affect crop plants limiting growth and yield potential. Structural and functional characterization of drought stress-induced genes has contributed to a better understanding of how plants respond and adapt to the drought stress. In the present study, differential display technique was employed to study the gene expression of rice plants at the reproductive stage that were subjected to drought stress by withholding water, Pseudomonas fluorescens strain (Pf1) treated plants subjected for drought stress by withholding water and control (well-watered). Differentially expressed cDNAs of six genes (COX1, PKDP, bZIP1, AP2-EREBP, Hsp20 and COC1) were identified, cloned and sequenced. Real-time qPCR analysis showed that all the six genes were upregulated in drought-stressed plants treated with Pf1. This revealed that the remarkable influence of Pf1 colonization leads to drought tolerance at the reproductive stage. These results showed that high levels of gene expression in plants lacking adequate water can be remarkably influenced by Pf1 colonization, which might be a key element for induced systemic tolerance by microbes.

Plants dispense localised and systemic defense responses against biotic colonisers and plant resistance to pathogens depends upon timely recognition of pathogen infection and subsequent rapid activation of defense responses through signal transduction pathways. Induction of host defense responses involving compatible and incompatible interactions in tomato landrace, LE996, LE150 and LE1165 (Solanum lycopersicum), and wild relatives, Seijima Jeisei and I979 (S. hirsutum) genotypes, and early blight (EB) pathogen, Alternaria solani were studied. Accumulation patterns of different defense related proteins in resistant genotypes (LE996, Seijima jeisei and I979) and susceptible genotypes (LE150 and LE1165) are reported here. Challenge inoculation led to similar protein profiles in resistant genotypes yielding 11 proteins, unique are 14, 54, and 58 kD proteins that are absent with susceptible genotypes. Resistant genotypes accumulated more proteins well in advance, 6-h after challenge inoculation. Resistant gen...

Shoot and fruit borer, Leucinodes orbonalis (Guenee) (Pyraustidae: Lepidoptera), has become a production constraint in all eggplant (Solanum melongena Linn. [Solanaceae])-growing countries. In India, transgenic eggplants expressing Bacillus thuringiensis Cry toxins have been tested in fields by private- and public-sector agencies. Understanding population diversity is important in designing strategies for better pest management. In the present investigation, random-amplified polymorphic DNA markers were used to assess the genetic diversity of L. orbonalis population collected from different field locations in the Tamilnadu State of India. Of 17 random-amplified polymorphic DNA primers screened, only 11 primers generated polymorphic bands (up to 14 bands). According to their level of similarities, only two major clusters with no variation among population were deduced. Our results indicated that there is a steady genetic flow among the present population of L. orbonalis alleviating genetic variation, which may be attributed to passive and active dispersal of the insect besides absence of host-induced variations among the population. As molecular variability of L. orbonalis population is an important consideration for shoot and fruit damage of the eggplant, constant monitoring is essential to study the possible development of Cry protein resistance in L. orbonalis.

Problem statement: Whitefly, Bemisia tabaci is an important sucking pest of field, horticultural and ornamental plants causing feeding injuries besides spreading disease by acting as a vector of Gemini viruses. The polyphagous nature of the pest makes it as a highly complex species. Approach: The influence of host plants utilized by the species on the population differences at molecular level was attempted using Random Amplified Polymorphic DNA (RAPD) markers. Results: Ten RAPD primers out of the total seventeen primers screened produced 236 markers. The total number of bands obtained from each primer ranged from 11-35 with an average of 23.60 bands per primer. Of the pair wise combination among thirteen species, Srivilliputhur population showed the highest similarity index (0.826) while the lowest (0.111) was recorded by Namakkal population. The similarity coefficient based on the 236 RAPD markers generated ranged from 0.111-0.826. Three major clusters were formed from UPGMA dendrogram, which was constructed based on Jaccard’s similarity. PCR screening demarcated the whitefly population based on the host species. The first cluster included population collected from okra and cotton, while second cluster comprised of population from eggplant and cauliflower and the third cluster included population from eggplant. It could be deduced that population from cotton and okra had 50% similarity, while 60-70% similarity was observed for population from eggplant and cauliflower. Conclusion: Our investigation offered the lead that within a narrow geographical region there exits variation based on host plants being utilized by the whitefly population.