Maize and heat stress: Physiological, genetic, and molecular insights

Abstract

Global mean temperature is increasing at a rapid pace due to the rapid emission of greenhouse gases majorly from anthropogenic practices and predicted to rise up to 1.5°C above the pre‐industrial level by the year 2050. The warming climate is affecting global crop production by altering biochemical, physiological, and metabolic processes resulting in poor growth, development, and reduced yield. Maize is susceptible to heat stress, particularly at the reproductive and early grain filling stages. Interestingly, heat stress impact on crops is closely regulated by associated environmental covariables such as humidity, vapor pressure deficit, soil moisture content, and solar radiation. Therefore, heat stress tolerance is considered as a complex trait, which requires multiple levels of regulations in plants. Exploring genetic diversity from landraces and wild accessions of maize is a promising approach to identify novel donors, traits, quantitative trait loci (QTLs), and genes, which can be introgressed into the elite cultivars. Indeed, genome wide association studies (GWAS) for mining of potential QTL(s) and dominant gene(s) is a major route of crop improvement. Conversely, mutation breeding is being utilized for generating variation in existing populations with narrow genetic background. Besides breeding approaches, augmented production of heat shock factors (HSFs) and heat shock proteins (HSPs) have been reported in transgenic maize to provide heat stress tolerance. Recent advancements in molecular techniques including clustered regularly interspaced short palindromic repeats (CRISPR) would expedite the process for developing thermotolerant maize genotypes.

Temperature‐smart plants: A new horizon with omics‐driven plant breeding

“…Extreme weather conditions significantly disrupt various metabolic processes in plants (Figure 2C) (Raza et al, 2021c;Zandalinas and Mittler, 2022;Djalovic et al, 2023;Raza et al, 2023e;Raza et al, 2024;Saeed et al, 2023). The phenological phase of plants has an optimum temperature range for normal growth and development, and temperature fluctuations significantly impact growth, leading to crop loss and food shortages (Raza et al, 2021c;Raza et al, 2022a;Djalovic et al, 2023;Raza et al, 2023c;Raza et al, 2023e;Saeed et al, 2023).…”

“…Extreme weather conditions significantly disrupt various metabolic processes in plants (Figure 2C) (Raza et al, 2021c;Zandalinas and Mittler, 2022;Djalovic et al, 2023;Raza et al, 2023e;Raza et al, 2024;Saeed et al, 2023). The phenological phase of plants has an optimum temperature range for normal growth and development, and temperature fluctuations significantly impact growth, leading to crop loss and food shortages (Raza et al, 2021c;Raza et al, 2022a;Djalovic et al, 2023;Raza et al, 2023c;Raza et al, 2023e;Saeed et al, 2023). Recent data indicates that for every 1 C increase in the global average temperature, maize (Zea mays L.), wheat (Triticum aestivum L.), rice (Oryza sativa L.), and soybean (Glycine max L.) production is projected to decrease by 7.4, 6.0, 3.2 and 3.1%, respectively, on average (Ding and Yang, 2022).…”

“…The agricultural sector, heavily reliant on stable climate conditions, is particularly vulnerable, resulting in widespread yield losses on a global scale (Zandalinas et al, 2021; Farooq et al, 2022; Rivero et al, 2022; Benitez‐Alfonso et al, 2023). Climate change contributes to the increase in the frequency and severity of various abiotic stresses, including temperature, salinity, drought, and flooding, which adversely affect crop production (Figure 2A) (Raza et al, 2019; Zandalinas et al, 2021; Farooq et al, 2022; Gonzalez et al, 2022; Rivero et al, 2022; Benitez‐Alfonso et al, 2023; Djalovic et al, 2023; Varshney and Bohra, 2023; Zandalinas et al, 2023). These repercussions of climate change are predicted to affect agricultural yields in the years ahead (Figure 2B).…”

“…Crops in field environments experience a wide range of temperature stress, including heat stress (HS; >25 C), chilling stress (CS; 0-15 C), and freezing stress (FS; <0 C), which seriously threaten agricultural food production (Zhang et al, 2019;Raza et al, 2021c;Zandalinas and Mittler, 2022;Raza et al, 2023e;Raza et al, 2024;Saeed et al, 2023). In response to these extreme temperatures, plants use a range of morphological, physiological, biochemical, molecular and cellular adaptations, which have been reviewed extensively in recent literature (Zhang et al, 2019;Raza et al, 2021c;Zandalinas and Mittler, 2022;Sharma et al, 2022;Ding and Yang, 2022;Djalovic et al, 2023;Raza et al, 2023c;Raza et al, 2023e;Saeed et al, 2023). Temperature stress, whether in isolation or combined with other stressors, can induce oxidative damage in plants (Zandalinas et al, 2018;Mittler et al, 2022;Zandalinas and Mittler, 2022).…”

“…Temperature stress, whether in isolation or combined with other stressors, can induce oxidative damage in plants (Zandalinas et al, 2018;Mittler et al, 2022;Zandalinas and Mittler, 2022). Consequently, HS and CS impede plant development by causing cellular injury or even cell death, leading to reduced membrane fluidity, decreased antioxidant enzyme activities, altered biosynthesis of various proteins and secondary metabolites, and changes in hormonal signaling and source-sink relationships after prolonged exposure (Zhang et al, 2019;Abdelrahman et al, 2020;Raza et al, 2021c;Sharma et al, 2022;Ding and Yang, 2022;Kumar et al, 2022;Raza, 2022;Raza et al, 2023c;Djalovic et al, 2023;Raza et al, 2023e;Raza et al, 2024;Saeed et al, 2023). Understanding how plants adapt to, respond to, and tolerate temperature fluctuations is crucial for enhancing plant productivity under changing climatic conditions.…”