Feeling the heat: developmental and molecular responses of wheat and barley to high ambient temperatures

Abstract

The increasing demand for global food security in the face of a warming climate is leading researchers to investigate the physiological and molecular responses of cereals to rising ambient temperatures. Wheat and barley are temperate cereals whose yields are adversely affected by high ambient temperatures, with each 1 °C increase above optimum temperatures reducing productivity by 5–6%. Reproductive development is vulnerable to high-temperature stress, which reduces yields by decreasing grain number and/or size and weight. In recent years, analysis of early inflorescence development and genetic pathways that control the vegetative to floral transition have elucidated molecular processes that respond to rising temperatures, including those involved in the vernalization- and photoperiod-dependent control of flowering. In comparison, our understanding of genes that underpin thermal responses during later developmental stages remains poorly understood, thus highlighting a key area for future research. This review outlines the responses of developmental genes to warmer conditions and summarizes our knowledge of the reproductive traits of wheat and barley influenced by high temperatures. We explore ways in which recent advances in wheat and barley research capabilities could help identify genes that underpin responses to rising temperatures, and how improved knowledge of the genetic regulation of reproduction and plant architecture could be used to develop thermally resilient cultivars.

Characterization of novel pollen-expressed transcripts reveals their potential roles in pollen heat stress response in Arabidopsis thaliana

“…High temperatures have profound harmful effects on plants' reproduction, often causing severe damages to complete loss of crops (Slattery and Ort 2019;Jacott and Boden 2020;Lohani et al 2020). The male gametophyte is thought to be the most sensitive to heat stress (HS) compared to all other organs and tissues in most plants, including the female gametophyte (Zinn et al 2010;Muller and Rieu 2016;Rieu et al 2017).…”

The Heat is On: How Crops Respond to High Temperature

“…InArabidopsis , high temperature is able to induce the expression of flowering-promoting genes, such as FLOWERING LOCUS T (FT ) under non-inductive SD (Casal & Balasubramanian, 2019;Vu et al, 2019). In contrast, transcript levels of the barley and wheat ortholog of FLOWERING LOCUS T1 (FT1 ), do not increase upon high temperature treatments in short days (Dixon et al, 2018;Hemming et al, 2012;Kiss et al, 2017), suggesting FT1 -independent high temperature responsiveness of flowering in cereals (Jacott & Boden, 2020). In maize, time to tasseling is advanced by higher temperature, but there is no effect on the silking time .…”

Characterizing the putative mitogen-activated protein kinase (MAPK) and their protective role in oxidative stress tolerance and carbon assimilation in wheat under terminal heat stress

“…have severe impact on the yield and grain-quality of wheat across the globe [ 3 ]. Terminal HS is defined as an elevation in temperature above ambient (>32 °C) during flowering and grain-filling stages [ 4 , 5 ]. Terminal HS has severe effect on different biological processes operating inside the plant system causing enormous losses in grain yield.…”