Genome-wide transcriptomic analysis of cotton under drought stress reveal significant down-regulation of genes and pathways involved in fibre elongation and up-regulation of defense responsive genes

Abstract

Cotton is an important source of natural fibre used in the textile industry and the productivity of the crop is adversely affected by drought stress. High throughput transcriptomic analyses were used to identify genes involved in fibre development. However, not much information is available on cotton genome response in developing fibres under drought stress. In the present study a genome wide transcriptome analysis was carried out to identify differentially expressed genes at various stages of fibre growth under drought stress. Our study identified a number of genes differentially expressed during fibre elongation as compared to other stages. High level up-regulation of genes encoding for enzymes involved in pectin modification and cytoskeleton proteins was observed at fibre initiation stage. While a large number of genes encoding transcription factors (AP2-EREBP, WRKY, NAC and C2H2), osmoprotectants, ion transporters and heat shock proteins and pathways involved in hormone (ABA, ethylene and JA) biosynthesis and signal transduction were up-regulated and genes involved in phenylpropanoid and flavonoid biosynthesis, pentose and glucuronate interconversions and starch and sucrose metabolism pathways were down-regulated during fibre elongation. This study showed that drought has relatively less impact on fibre initiation but has profound effect on fibre elongation by down-regulating important genes involved in cell wall loosening and expansion process. The comprehensive transcriptome analysis under drought stress has provided valuable information on differentially expressed genes and pathways during fibre development that will be useful in developing drought tolerant cotton cultivars without compromising fibre quality.

Understanding the molecular events underpinning cultivar differences in the physiological performance and heat tolerance of cotton (Gossypium hirsutum)

“…Although cotton-specific heat-responsive genes have been identified under drought stress at a molecular level (Rodriguez-Uribe and Zhang 2009; Payton et al 2011;Padmalatha et al 2012;Park et al 2012), the heat stress response of cotton plants under elevated temperature and well watered conditions has not yet been characterised. To determine the heat stress response of cotton, heat-responsive genes and pathways were identified for leaves sampled under after 1 h incubation at either control (32 C) or elevated (42 C) temperatures in the growth cabinet.…”

GhDRIN1, a novel drought-induced gene of upland cotton (Gossypium hirsutum L.) confers abiotic and biotic stress tolerance in transgenic tobacco

“…The gene was named as G. hirsutum drought-induced 1 (GhDRIN1). It was upregulated in drought-induced samples at 135-, 243-and 2.5-fold at 5, 10 and 20 dpa, respectively, compared to the controls (Padmalatha et al 2012). The upregulation of the same transcript was also observed in bollworm (Helicoverpa armigera) infested cotton boll samples for 8-, 19.5-, 128-, 575-fold more at 0, 2, 5, 10 dpa (unpublished data), respectively, compared to the control samples as revealed in the transcriptome based microarray study.…”

“…Drought stress induction under field condition and related parameters were followed as described previously (Padmalatha et al 2012). The bollworm infected cotton bolls were collected from the field-grown plants.…”

“…A number of hypothetical uncharacterized/unpredicted proteins which are highly expressed in cotton boll tissues subjected to drought stress were identified (Padmalatha et al 2012). Although the transcriptomic data can give us insights into various process and key genes involved in a particular response, it is important to validate the gene function to determine its ability to impart stress tolerance/resistance to the plants.…”

Physiological adaptations to osmotic stress and characterization of a polyethylene glycol-responsive gene in Braya humilis

“…In general, stress-resistant genes can be divided into two major groups according to their functions. One group plays a crucial role in avoiding cell damage, while the second group is involved in signal transduction and transcription regulation [20]. In particular, calcineurin B-like proteins (CBLs) and CBL-interacting protein kinases (CIPKs) constitute an important Ca 2+ signaling network that copes with various biotic and abiotic stresses [21].…”