Identification of drought tolerant progenies in tea by gene expression analysis

Abstract

Understanding the genes that govern tea plant (Camellia sinensis) architecture and response to drought stress is urgently needed to enhance breeding in tea with improved water use efficiency. Field drought is a slow mechanism and the plants go through an adaptive process in contrast to the drastic changes of rapid dehydration in case of controlled experiments. We identified a set of drought responsive genes under controlled condition using SSH, and validated the identified genes and their pattern of expression under field drought condition. The study was at three stages of water deficit stress viz., before wilting, wilting and recovery, which revealed a set of genes with higher expression at before wilting stage including dehydrin, abscissic acid ripening protein, glutathione peroxidase, cinnamoyl CoA reductase, calmodulin binding protein. The higher expression of these genes was related with increase tolerance character of DT/TS-463 before wilting, these five tolerant progenies could withstand drought stress and thus are candidates for breeding. We observed that physiological parameter like water use efficiency formed a close group with genes such as calmodulin related, DRM3, hexose transporter, hydrogen peroxide induced protein, ACC oxidase, lipase, ethylene responsive transcription factor and diaminopimelate decarboxylase, during wilting point. Our data provides valuable information for the gene components and the dynamics of gene expression in second and third leaf against drought stress in tea, which could be regarded as candidate targets potentially associated with drought tolerance. We propose that the identified five tolerant progenies on the basis of their drought tolerance can thus be utilised for future breeding programmes.

A genomic perspective on the important genetic mechanisms of upland adaptation of rice

“…The GDSL domain-containing lipase has been reported to be involved in response to abiotic stress, such as drought [25-27], indicating that the genetic differentiation of these genes in upland rice may be relevant to their adaption to dry land. Peroxidases and glutathione-related proteins bear antioxidant activity, another crucial factor in plant adaptation to a drought-like environment [6,7].…”

Physiological changes and differential gene expression of tea plant under dehydration and rehydration conditions

“…DS signal perception and transduction by plants cells induced the expression of regulatory and functional sets of genes (Gupta et al, 2012(Gupta et al, , 2013. By comparing the expression of five droughtrelated genes in cultivars during the different phases of DS, we found that the expression levels of five genes were differentially up-regulated under DS.…”

“…However, few studies have focused on changes to the phytohormone content in tea plants experiencing DS; interaction of osmolytes, antioxidases and phytohormones in tea plants are not well understood under DS and rewatering. Furthermore, a set of drought responsive genes and their pattern of expression were identified by using cDNA-amplified fragment length polymorphism (cDNA-AFLP) and suppression subtractive hybridization (SSH) (Gupta et al, 2012(Gupta et al, , 2013. Nevertheless, during and after DS, comprehensive physiological and molecular studies on the responses of susceptible and tolerant mature field-grown tea cultivars are still lacking.…”

Transcriptome-based identification of water-deficit stress responsive genes in the tea plant,Camellia sinensis

“…Galactinol is induced in plants subjected to drought such as Cucumis melo (Volk et al 2003), Coffea arabica L. and Arabidopsis thaliana (Taji et al 2002). The induction of Gols in these species confers some level of drought tolerance (Gupta et al 2012). The expression of galactinol synthase gene in the drought tolerant cultivar TRFCA SFS150 corroborated the role of this gene in defense against stress…”

“…Another category of transcripts that showed homology with heat shock proteins (HSP70-1), were induced in the test cultivars under water stress conditions. Heat shock proteins serve as intra-cellular chaperones for other proteins and are also involved in plant stress response (Gupta et al 2012). HSPs are involved in protection by controlling protein folding and protection of macromolecules and membranes from dehydration during drought (Das et al 2012).…”