The RING Finger Ubiquitin E3 Ligase OsHTAS Enhances Heat Tolerance by Promoting H2O2-Induced Stomatal Closure in Rice

Abstract

Heat stress often results in the generation of reactive oxygen species, such as hydrogen peroxide, which plays a vital role as a secondary messenger in the process of abscisic acid (ABA)-mediated stomatal closure. Here, we characterized the rice (Oryza sativa) HEAT TOLERANCE AT SEEDLING STAGE (OsHTAS) gene, which plays a positive role in heat tolerance at the seedling stage. OsHTAS encodes a ubiquitin ligase localized to the nucleus and cytoplasm. OsHTAS expression was detected in all tissues surveyed and peaked in leaf blade, in which the expression was concentrated in mesophyll cells. OsHTAS was responsive to multiple stresses and was strongly induced by exogenous ABA. In yeast two-hybrid assays, OsHTAS interacted with components of the ubiquitin/26S proteasome system and an isoform of rice ascorbate peroxidase. OsHTAS modulated hydrogen peroxide accumulation in shoots, altered the stomatal aperture status of rice leaves, and promoted ABA biosynthesis. The results suggested that the RING finger ubiquitin E3 ligase OsHTAS functions in leaf blade to enhance heat tolerance through modulation of hydrogen peroxide-induced stomatal closure and is involved in both ABA-dependent and DROUGHT AND SALT TOLERANCE-mediated pathways.

Molecular mechanisms governing plant responses to high temperatures

“…Multiple studies have shown that the ability to clean up unfolded proteins corresponds to the ability of plants to survive exposure to extreme HT. For example, plants deficient in the expression of proteasome subunits (Li et al ), E3 ligases, and autophagy‐related genes (Zhou et al , ; Liu et al ; Gil et al ) are susceptible to HS. Moreover, transgenic plants overexpressing genes encoding either ubiquitin (Tian et al ) or ubiquitin E3 ligases (Lim et al ; Liu et al ; Liu et al ) exhibit enhanced basal and/or acquired heat tolerance.…”

PeCHYR1, a ubiquitin E3 ligase from Populus euphratica, enhances drought tolerance via ABA‐induced stomatal closure by ROS production in Populus

“…Recently, it was reported that ROS can induce stomatal closure through an ABA‐independent pathway in rice ( Oryza sativa ). The SNAC1‐targeted gene OsSRO1c positively controls H 2 O 2 ‐induced stomatal closure by regulating hydrogen peroxide level in rice, and the E3 ligase OsHTAS can promote heat tolerance by modulating H 2 O 2 ‐induced stomatal closure in rice (Liu et al ., ; You et al ., ). However, 35S: OsASR5 plants were more sensitive to exogenous ABA treatment, activating the production of H 2 O 2 (Li et al ., ).…”

Molecular characterization and function analysis of the rice OsDUF946 family

“…Rice (Oryza sativa), as a dietary staple for almost two-thirds of the world's population, is one of the most important agricultural crops. Recently, some genes have been used successfully to improve the tolerance of rice to stresses [23][24][25][26][27][28].…”