Global dissection of the BAHD acyltransferase gene family in soybean: Expression profiling, metabolic functions, and evolution

Abstract

Background: Members of the BAHD acyltransferase (ACT) family play important roles in plant defence against biotic and abiotic stresses. A better understanding of the functions that specific members of this family play in stress defence can lead to better breeding strategies for stress tolerance. Previous genome-wide studies explored other acyltransferase families, but so far not a single study has been published on genome-wide or positive selection analyses of the BAHD genes in Glycine max . Results: A total of 103 genes of the BAHD family (GmACT genes) were identified from the soybean genome, which could be grouped into four phylogenetic clades (I-IV). Clade III was further divided into two sub-clades (IIIA and IIIB). In each clade, the gene structure and functional motifs were relatively well conserved. These ACT genes were unequally distributed on all 20 chromosomes, and 16 paralogous pairs were found within the family. Positive selection analysis revealed amino acids under strong positive selection, which suggests that the evolution of this gene family modulated soybean domestication. Some GmACT genes showed expression specific under specific conditions, while others showed constitutive expression in all soybean tissues or conditions analysed. Most of the expression of ACT genes in soybean was repressed with Al 3+ and fungal elicitor exposure, except for GmACT84 , which expression increased in these conditions 2- and 3-fold, respectively. The promoter of GmACT84 contains the maximum number of stress-responsive elements among all GmACT genes and it is especially enriched in MYB-related elements. Conclusions: This study provides a genome-wide analysis of the BAHD gene family and assessed their expression profiles in soybean. We found evidence of a strong positive selection of GmACT genes. Our findings will help efforts of functional characterisation of ACT genes in soybean in order to discover their involvement in growth, development, and defence mechanisms.

Identification and analysis of BAHD superfamily related to malonyl ginsenoside biosynthesis in Panax ginseng

“…Malonyltransferase Ss5MaT2, although also associated with acyl modification, is classified in clade III because it does not contain conserved sequences common to clade I. Therefore, attention will also be paid to PgBAHD14,30,46,61,62,73,74 and 88. Based on sequence structure, physicochemical properties, function, and distribution on chromosomes, the identified PgBAHDs showed a high degree of diversity, which is consistent with previous reports on BAHD gene families (Moglia et al, 2016;Zhang et al, 2019;Ahmad et al, 2020;Liu et al, 2020b).…”

A recently evolved BAHD acetyltransferase, responsible for bitter soyasaponin A production, is indispensable for soybean seed germination

“…The soybean genome encodes 103 BAHD acyltransferases, which can be classified into four clades (I–IV) (Ahmad et al, 2020). We implemented a co‐expression analysis strategy to identify putative GmSSAcT genes in the soyasaponin biosynthetic pathway using 12 functional known soyasaponin genes, including β‐amyrin synthase1 ( GmBAS1 ), three cytochrome P450 genes CYP93E1 , CYP72A61 , CYP72A69 and eight glycosyltransferase genes UGT73F2 , UGT73B4 , UGT73P2 , UGT91H4 , UGT91H9 , UGT73F2 , CSyGT1 , and SSAT1 .…”

“…Phylogenetic analysis suggested that soybean gained SSAcT activity after its separation from other leguminous plants. Clustered with six other ACT genes ( Glyma18G268100 , Glyma18G268200 , Glyma18G268400 , Glyma18G268500 , Glyma18G268600 , and Glyma18G271600 ; all annotated as flavone/isoflavone malonyltransferases) on chromosome 18 in the soybean genome (Ahmad et al, 2020), GmSSAcT1 probably arose from a flavone/isoflavone malonyltransferase gene by gene duplication and neofunctionalization, coupled with a change in expression pattern, given that flavone/isoflavones are widely distributed in leguminous plants (Panchy et al, 2016). The selection pressure imposed by null‐acetyl type‐A soyasaponins on seed germination allowed the fixation of the recently evolved GmSSAcT1 in the soybean population.…”