Leaf transcriptome analysis of Lancaster versus other heterotic groups’ maize inbred lines revealed different regulation of cold‐responsive genes

Abstract

One of the strategies for overcoming global climate change threatening to decrease maize yield is early sowing. To contribute to the development of cold‐tolerant hybrids this research focused on the genetic background's comparative analysis in maize inbreds with good combining ability. Leaf whole‐transcriptome sequencing of 46 maize genotypes revealed 77 differentially expressed genes (DEGs) between Lancaster and other heterotic groups (i.e. BSSS, Iowa dent, Ohio), referred to as non‐Lancaster group, under optimal growing conditions. Cold test of the subset of four Lancaster and four non‐Lancaster lines showed that the former were cold sensitive and the latter cold tolerant. Cold‐induced expression analysis of seven DEGs in eight lines revealed different expression regulation dependent on the duration of cold exposure and genetic background for six out of seven analysed genes—chloroplast ATP‐sulphurylase, photosystem II cytochrome b559 alpha subunit, CIPK serine‐threonine protein kinase 15, glutamyl‐tRNA reductase, photosystem II reaction centre protein I and Calvin cycle CP12‐chloroplastic‐like encoding genes. The results imply that differently regulated basic processes between Lancaster and non‐Lancaster maize group involve, at least, photosynthesis and sulphate assimilation, contributing to their different cold response and different adaptation to low temperatures.

Can we improve the chilling tolerance of maize photosynthesis through breeding?

“…While not as rapid as the decreases in CO 2 assimilation and PSII operating efficiency, down-regulation of photosynthetic gene expression (i.e. the abundance of photosynthesis-related transcripts) has been reported as early as 4 h after the beginning of chilling stress ( Li et al , 2019 ), after 12 h in another study ( Yu et al , 2021 ), and after 1 d of chilling stress in several studies ( Trzcinska-Danielewicz et al , 2009 ; Zhang et al , 2009 ; Jończyk et al , 2017 ; Avila et al , 2018 ; Banović Đeri et al , 2021 ). A decrease in photosynthetic protein accumulation occurs soon after, reported after 2 d of chilling stress ( Urrutia et al , 2021 ).…”

A Trajectory of Discovery: Metabolic Regulation by the Conditionally Disordered Chloroplast Protein, CP12

“…In addition to the expected functions, a potential role for CP12 in chilling tolerance has been suggested [ 80 ]. A recent transcriptomic analysis of maize also revealed the different regulations of cold-responsive genes and, among them, the CP12 gene is present [ 90 ].…”