CcNFYB3‐CcMATE35 and LncRNA CcLTCS‐CcCS modules jointly regulate the efflux and synthesis of citrate to enhance aluminium tolerance in pigeon pea

Abstract

SummaryAluminium (Al) toxicity decreases crop production in acid soils in general, but many crops have evolved complex mechanisms to resist it. However, our current understanding of how plants cope with Al stress and perform Al resistance is still at the initial stage. In this study, the citrate transporter CcMATE35 was identified to be involved in Al stress response. The release of citrate was increased substantially in CcMATE35 over‐expression (OE) lines under Al stress, indicating enhanced Al resistance. It was demonstrated that transcription factor CcNFYB3 regulated the expression of CcMATE35, promoting the release of citrate from roots to increase Al resistance in pigeon pea. We also found that a Long noncoding RNA Targeting Citrate Synthase (CcLTCS) is involved in Al resistance in pigeon pea. Compared with controls, overexpression of CcLTCS elevated the expression level of the Citrate Synthase gene (CcCS), leading to increases in root citrate level and citrate release, which forms another module to regulate Al resistance in pigeon pea. Simultaneous overexpression of CcNFYB3 and CcLTCS further increased Al resistance. Taken together, these findings suggest that the two modules, CcNFYB3‐CcMATE35 and CcLTCS‐CcCS, jointly regulate the efflux and synthesis of citrate and may play an important role in enhancing the resistance of pigeon pea under Al stress.

Underground communication: Long non-coding RNA signaling in the plant rhizosphere

“…However, increasing citrate production is an appealing strategy for the generation of Al-tolerant transgenic plants. The citrate synthase enzyme catalyzes the first step of the tricarboxylic acid (TCA) cycle, condensing acetyl-coenzyme A and oxaloacetate to produce citrate ( Gupta and Gupta, 2021 ), and Long non-coding RNA Targeting Citrate Synthase ( CcLTCS ) has been shown to positively regulate transcription of the Citrate Synthase gene ( CcCS ) in pigeon pea ( Dong et al., 2023 ). CcLTCS lacks protein-coding potential, implying that it regulates CcCS through mechanisms other than encoding a protein.…”

“…Alternatively, CcLTCS might engage with transcription factors to regulate CcCS expression or bind to CcCS mRNA to influence splicing. More research is required to reveal the precise molecular mechanism by which CcLTCS regulates the expression of citrate synthase ( Dong et al., 2023 ).…”