MsMYB741 is involved in alfalfa resistance to aluminum stress by regulating flavonoid biosynthesis. (23rd September 2022)

• Record Type: Journal Article
• Authors: Su, Liantai; Lv, Aimin; Wen, Wuwu; Fan, Nana; Li, Jiaojiao; Gao, Li; Zhou, Peng; An, Yuan
• Is Part Of: Plant journal. Volume 112:Number 3(2022)
• Page Start: 756
• Page End: 771
• Publication Date: 2022-09-23
• Subjects: MYB transcription factor -- aluminum toxicity -- MsPAL1 -- MsCHI -- MsABF2 -- ABRE element; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.15977
• Languages: English
• ISSNs: 0960-7412

Abstract

SUMMARY: Aluminum (Al) toxicity severely restricts plant growth in acidic soils (pH < 5.0). In this study, an R2R3‐MYB transcription factor (TF) gene, MsMYB741, was cloned from alfalfa. Its function and gene regulatory pathways were studied via overexpression and RNA interference of MsMYB741 in alfalfa seedlings. Results showed that root elongation increased as a result of MsMYB741 overexpression ( MsMYB741 ‐OE) and decreased with MsMYB741 RNA interference ( MsMYB741 ‐RNAi) in alfalfa seedlings compared with the wild‐type under Al stress. These were attributed to the reduced Al content in MsMYB741 ‐OE lines, and increased Al content in MsMYB741 ‐RNAi lines. MsMYB741 positively activated the expression of phenylalanine ammonia‐lyase 1 ( MsPAL1 ) and chalcone isomerase ( MsCHI ) by binding to MYB and ABRE elements in their promoters, respectively, which directly affected flavonoid accumulation in roots and secretion from root tips in plants under Al stress, eventually affecting Al accumulation in alfalfa. Additionally, MsABF2 TF directly activated the expression of MsMYB741 by binding to the ABRE element in its promoter. Taken together, our results indicate that MsMYB741 transcriptionally activates MsPAL1 and MsCHI expression to increase flavonoid accumulation in roots and secretion from root tips, leading to increased resistance of alfalfa to Al stress. Significance Statement: MsMYB741 is a key MYB transcription factor that promotes aluminum resistance of alfalfa via regulating flavonoid biosynthesis and secretion through directly activating MsPAL1 and MsCHI expression. Additionally, MsMYB741 is targeted by MsABF2, which is activated by ABA.