Natural variation of HTH5 from wild rice, Oryza rufipogon Griff., is involved in conferring high‐temperature tolerance at the heading stage

Abstract

Summary Global warming is a major abiotic stress factor, which limit rice production. Exploiting the genetic basis of the natural variation in heat resistance at different reproductive stages among diverse exotic Oryza germplasms can help breeding heat‐resistant rice cultivars. Here, we identified a stable quantitative trait locus (QTL) for heat tolerance at the heading stage on chromosome 5 (qHTH5) in O. rufipogon Griff. The corresponding gene, HTH5, pertains to the pyridoxal phosphate‐binding protein PLPBP (formerly called PROSC) family, which is predicted to encode pyridoxal phosphate homeostasis protein (PLPHP) localized to the mitochondrion. Overexpression of HTH5 increased the seed‐setting rate of rice plants under heat stress at the heading stage, whereas suppression of HTH5 resulted in greater susceptibility to heat stress. Further investigation indicated that HTH5 reduces reactive oxygen species accumulation at high temperatures by increasing the heat‐induced pyridoxal 5'‐phosphate (PLP) content. Moreover, we found that two SNPs located in the HTH5 promoter region are involved with its expression level and associated with heat tolerance diversity. These findings suggest that the novel gene HTH5 might have great potential value for heightening rice tolerance to heat stress to the on‐going threat of global warming.

QTL mapping and identification of candidate genes using a genome-wide association study for heat tolerance at anthesis in rice (Oryza sativa L.)

“… Chen et al (2019) identified AET1 , a tRNA His guanylytransferase, which regulates auxin signaling in response to high temperatures and the environmental temperature response in rice. Cao et al (2022) identified HTH5 from Oryza rufipogen Griff, which reduced reactive oxygen species accumulation at high temperatures by increasing the level of the heat-induced pyridoxal 5′-phosphate, increasing pollen vitality, and thereby improving spikelet fertility. The heat tolerance QTL qHTSF4.1 was introgressed into the IR64 background using the molecular marker-assisted selection method and the near isogenic lines IR64HT 4 were developed.…”

High‐temperature stress in crops: male sterility, yield loss and potential remedy approaches

“…Likewise, in emmer wheat, the alleles (Ppd-A1) are associated with early flowering (Nishimura et al, 2018), while the QTL that suppressed the late flowering in emmer wheat was detected on 7B chromosome and is linked to the Vrn-B3 gene (Wright et al, 2020), which will be helpful in protecting plant from male sterility during HT stress. Similarly, in rice, Cao et al (2022) found a QTL (qHTH5) in Oryza rufipogon at chromosome 5 and transfered it to Oryza sativa, which increased the tolerance in O. sativa at the heading stage, while its suppression increased its susceptibility to HT stress. Furthermore, in rice, the early flowering traits were transferred from EMF20 in O. sativa to develop HT tolerant rice by Hirabayashi et al (2015).…”

“…Similarly, in rice, Cao et al . (2022) found a QTL ( qHTH5 ) in Oryza rufipogon at chromosome 5 and transfered it to Oryza sativa , which increased the tolerance in O. sativa at the heading stage, while its suppression increased its susceptibility to HT stress. Furthermore, in rice, the early flowering traits were transferred from EMF20 in O. sativa to develop HT tolerant rice by Hirabayashi et al .…”

“…When the temperature rises frequently to 10–15 °C beyond the ambient temperature for a short period of time, it is described as heat shock or heat stress. HT is a major abiotic stress factor, which limits the crop production (Cao et al ., 2022) and causes harmful effects on plants, including denaturation of proteins, inhibition of protein synthesis, protein degradation and altered lipid membrane fluidity and integrity (Howarth, 2005; Zhang et al ., 2022a). Globally, many species of the crops are sensitive to the HT stress, which ultimately affects countries' economies by reducing the crop production (Abbas, 2022).…”

The Conserved Family of the Pyridoxal Phosphate-Binding Protein (PLPBP) and Its Cyanobacterial Paradigm PipY

“…In two of them, bacterial cells were engineered for PLPBP overexpression to address specific questions in the context of neighbor genes (see Section 4.1 ). However, the third report constitutes a unique example of an adaptative spontaneous mutation in a cereal crop, dealing with a natural variation in wild rice ( Oryza rufipogon ) conferring high-temperature tolerance at the phenological heading stage [ 55 ]. A map-based cloning approach for heat tolerance specifically at the panicle development stage identified qHTH5 as a major quantitative trait locus (QTL) and the target gene (encoding a PLPBP ortholog) was named HTH5 .…”