Cold tolerance response mechanisms revealed through comparative analysis of gene and protein expression in multiple rice genotypes

Abstract

Due to its tropical origin and adaptation, rice is significantly impacted by cold stress, and consequently sustains large losses in growth and productivity. Currently, rice is the second most consumed cereal in the world and production losses caused by extreme temperature events in the context of "major climatic changes" can have major impacts on the world economy. We report here an analysis of rice genotypes in response to low-temperature stress, studied through physiological gas-exchange parameters, biochemical changes in photosynthetic pigments and antioxidants, and at the level of gene and protein expression, towards an understanding and identification of multiple low-temperature tolerance mechanisms. The first effects of cold stress were observed on photosynthesis among all genotypes. However, the tropical japonica genotypes Secano do Brazil and Cypress had a greater reduction in gas exchange parameters like photosynthesis and water use efficiency in comparison to the temperate japonica Nipponbare and M202 genotypes. The analysis of biochemical profiles showed that despite the impacts of low temperature on tolerant plants, they quickly adjusted to maintain their cellular homeostasis by an accumulation of antioxidants and osmolytes like phenolic compounds and proline. The cold tolerant and sensitive genotypes showed a clear difference in gene expression at the transcript level for OsGH3-2 , OsSRO1a , OsZFP245 , and OsTPP1 , as well as for expression at the protein level for LRR-RLKs, bHLH, GLYI, and LTP1 proteins. This study exemplifies the cold tolerant features of the temperate japonica Nipponbare and M202 genotypes, as observed through the analysis of physiological and biochemical responses and the associated changes in gene and protein expression patterns. The genes and proteins showing differential expression response are notable candidates towards understanding the biological pathways affected in rice and for engineering cold tolerance, to generate cultivars capable of maintaining growth, development, and reproduction under cold stress. We also propose that the mechanisms of action of the genes analyzed are associated with the tolerance response.

Interactive Impacts of Temperature and Elevated CO2 on Basil (Ocimum basilicum L.) Root and Shoot Morphology and Growth

“…In contrast with the present results, previous studies have demonstrated that decreasing plant growth temperature significantly increased the chlorophyll index [41,42]. Many studies have utilized the plant chlorophyll index as a metric for characterizing the plant's tolerance to multiple abiotic stresses, especially temperature stress in grain and vegetables [41,43,44]. Low temperature significantly increased the non-destructive TCI of basil leaves by 18%.…”

Morpho-Physiological Characterization of Diverse Rice Genotypes for Seedling Stage High- and Low-Temperature Tolerance

“…Leaf growth is sensitive to various environmental stresses such as low temperature [18,32], water deficits [33], and nitrogen deficiency [34]. Generally, cold temperature slows the leaf initiation rate, reducing the leaf number, and directly lowering the leaf cell division and elongation [35,36], resulting in lower leaf and leaf dry weight. However, there was no effect of cold temperatures on leaf number in the present study (Figure 1C).…”

“…Cold stress reduces significantly the concentration of chlorophyll in susceptible rice genotypes [36,54]. Chlorophyll index was used as a tool to evaluate the degree of cold tolerance of transgenic plants [55] and ecotype [36], to monitor plant recovery after stress [56], and to compare chilling tolerance between distinct hybrid genotypes during grain filling [52]. On average, the non-destructive leaf chlorophyll index increased by 8% with increased temperature from optimum to high levels (Figure 4A).…”

Comparative analysis of two phytochrome mutants of tomato (Micro-Tom cv.) reveals specific physiological, biochemical, and molecular responses under chilling stress

“…As we found an obvious reduction in photosynthetic rate, stomatal conductance transpiration rate, along with some changes in fluorescence related parameters such as chlorophyll contents, in MT genotype under chilling stress, which support that the treatment has produced effective stress conditions. Previous reports have demonstrated such changes in physiological parameters under induced stress conditions in many plant species [ 43 , 44 ]. Under chilling stress, stomatal conductance, stomatal aperture, and transpiration rate were decreased in MT and aur mutant, which has been reflected by reduced photosynthetic rate in both genotypes (Figs.…”