2018 March Ph.D. Admissions (Final)

Friday seminar by Ms. Harsha samtani

PK Lab/ Friday/ January 4, 2019/ 3.30 pm/ Role of ABA in Heat Stress Response
Category: Research
Posted by: bedineel

Role of ABA in Heat Stress Response

Harsha Samtani

Plants being sessile organisms are severely affected by high temperatures. Even brief periods of heat stress (HS) can cause cellular damage. Plants thus have evolved processes like HS response (HSR) to overcome the lethal stress conditions. It is well documented that HSR leads to expression of Heat shock proteins (Hsps) via a heat shock factor (Hsf)-dependent mechanism. However, little is known about the signaling pathways resulting in expression of Hsfs and Hsps. Earlier studies have reported the role of phytohormone ABA in inducing thermotolerance. Recently, ABA signaling mutants were observed to be sensitive to HS, thereby indicating the potential role of ABA in thermotolerance response. In Arabidopsis, the non-heat inducible HsfA6b was found to function downstream of ABA, yet it positively regulated thermotolerance. Moreover, HsfA6b regulated DREB2A to turn on the downstream HS-responsive genes. Thus, ABA-regulated HsfA6b has a central role in providing heat stress resistance. Similarly, in case of wheat, TaHsfC2a was highly expressed in grains during grain filling and showed significant up-regulation by ABA. Most TaHsfC2a target genes were also co-upregulated in developing grains. It was found to function as a transcriptional activator of heat protection genes and thus serves as ABA-mediated proactive mechanism for heat protection in developing grains. In conclusion, these studies suggest that Hsfs might connect ABA signaling pathway with HSR.