AUTHOR=Yu Ming , Yu Yang , Guo Sihai , Zhang Mingfei , Li Nan , Zhang Shuangxing , Zhou Hongwei , Wei Fan , Song Tianqi , Cheng Jie , Fan Qiru , Shi Caiyin , Feng Wenhan , Wang Yukun , Xiang Jishan , Zhang Xiaoke 

TITLE=Identification of TaBADH-A1 allele for improving drought resistance and salt tolerance in wheat (Triticum aestivum L.)

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.942359

DOI=10.3389/fpls.2022.942359

ISSN=1664-462X

ABSTRACT=<p>Drought and salt stress can strongly affect the growth and development of wheat. Wheat adapts to drought and salt stress through osmotic regulation. Betaine aldehyde dehydrogenase (BADH) is a key enzyme in the synthesis of betaine, an osmotic regulator. We cloned a region of the <italic>TaBADH-A1</italic> promoter and genomic DNA that included the introns and exons, from four Chinese wheat cultivars. Following the analysis of <italic>TaBADH-A1</italic> genomic DNA and promoter sequence polymorphisms of 4 cloned and 15 cultivars from the database, 7 haplotypes of <italic>TaBADH-A1</italic> gene were identified. We divided the 7 haplotypes with a 254 bp insertion or deletion (indel) into two main alleles, <italic>BADH-A1a</italic> and <italic>BADH-A1b</italic>. Meanwhile, a molecular marker was developed based on the 254 bp indel of the third intron of <italic>TaBADH-A1</italic> gene. Expression levels of <italic>BADH-A1b</italic> were found to be significantly higher than those of <italic>BADH-A1a</italic> under drought and salt stress conditions. Betaine accumulation was significantly higher in wheat containing <italic>BADH-A1b</italic> compared to <italic>BADH-A1a</italic> under drought and salt stress. We also identified that the average relative germination and survival rates of wheat with the <italic>BADH-A1b</italic> allele were significantly higher than wheat with the <italic>BADH-A1a</italic> allele. The results reveal that wheat containing <italic>BADH-A1b</italic> has stronger drought and salt tolerance than wheat with <italic>BADH-A1a</italic>. Meanwhile, the geographic distribution and frequency of the <italic>TaBADH-A1</italic> locus alleles indicate that <italic>BADH-A1a</italic> has been preferred in Chinese wheat breeding programs, while <italic>BADH-A1b</italic>, associated with favorable stress tolerance, has been neglected. The results of this study provide evidence for an excellent candidate allele for marker-assisted selection of new wheat cultivars with increased salt tolerance and drought resistance.</p>