AUTHOR=Guo Hui , Tao Wei , Gao Huiyong , Chen Lei , Zhong Xiaoyuan , Tang Maoyan , Gao Guoqing , Liang Tianfeng , Zhang Xiaoli 

TITLE=Physiological traits, gene expression responses, and proteomics of rice varieties varying in heat stress tolerance at the flowering stage

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 15 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1489331

DOI=10.3389/fpls.2024.1489331

ISSN=1664-462X

ABSTRACT=Introduction/Background: Global warming greatly limits the productivity of rice. Rice plants are highly sensitive to heat stress at the flowering stage. The selection of heat-tolerant varieties is considered the most effective approach for ensuring global food security in the coming decades.Based on previous screening and QTL localization results, we selected tolerant varieties (Huang Huazhan, HZ) and susceptible varieties (Yang Dao6, YD) of rice and studied their physiological characteristics, gene expression responses, and proteomic differences of their anthers under heat stress. The differentially expressed proteins (DEPs) were validated by real-time PCR.The activities of the antioxidant enzymes CAT, SOD, POD, and APX were 8.36%, 9.56%, 20.61%, and 25.34% higher in HZ than in YD under heat stress, respectively. Similarly, the content of proline and soluble sugar was 9.08% and 14.47% higher in HZ than in YD, respectively. The content of MDA and H2O2 was 8.11% and 35.9% lower in HZ than in YD, respectively. The ratio of endogenous GA3/ABA in HZ was 10.65, which was significantly higher than that of YD (3.84). In addition, the expression of we validated the candidate gene LOC_Os08g07010 and LOC_Os08g07440 that our team located in 2021, and the result showed the expression of these two heat-tolerant genes in the anthers was significantly higher in HH than YHOsTT1 and TOGR1, which  was associated with heat stress, was significantly higher in HZ than in YD. DEPs involved in the response to heat stress were identified by TMT proteomics, five up-regulated and three downregulated differential expression proteins In HH. DEPs were verified by RT-qPCR. Discussion:These results provide new insights into the physiological characteristics, dominant DEPs, and gene expression responses in both rice varieties under heat stress. Our results indicate that the antioxidant and osmoregulatory capacities, the ratio content of endogenous GA3 and ABA, these DEPs are mainly involved in the pathways of phenylpropanoid biosynthesis, ubiquitin mediated proteolysis, carbohydrate metabolism, Thiamine metabolism, Protein processing in the endoplasmic reticulum, folding, sorting and degradation were up-regulated to a greater degree in HZ than in YD. Additional studies were performed to clarify the roles of these proteins in the response to heat stress.