Identification of a BAHD Acyltransferase Gene Involved in Plant Growth and Secondary Metabolism in Tea Plants

Abstract

Plant acyl-CoA dominated acyltransferases (named BAHD) comprise a large appointed protein superfamily and play varied roles in plant secondary metabolism like synthesis of modified anthocyanins, flavonoids, volatile esters, etc. Tea (Camellia sinensis) is an important non-alcoholic medicinal and fragrancy plant synthesizing different secondary metabolites, including flavonoids. In the tea (C.A sinensis) cultivar Longjing 43 (LJ43), eight samples were performed into three groups for transcriptome analysis under three biological replications. Among the BAHD acyltransferase genes in tea cultivars, the expression of TEA031065 was highest in buds and young leaves following the RNA sequencing data, which was coincident with the tissue rich in catechins and other flavonoids. We then transformed this gene into wild-type Arabidopsis as an over-expression (OX) line 1 and line 2 in ½ MS media to verify its function. In the wild types (WT), the primary root length, number of secondary roots, and total root weight were significantly higher at 24%, 15%, and 53.92%, respectively, compared to the transgenic lines (OX1 and OX2). By contrast, the leaves displayed larger rosettes (21.58%), with higher total leaf weight (32.64%) in the transgenic lines than in the wild type (WT). This result is consistent with DCR mutant At5g23940 gene in Arabidopsis thaliana. Here, anthocyanin content in transgenic lines was also increased (21.65%) as compared to WT. According to the RNA sequencing data, a total of 22 growth regulatory genes and 31 structural genes with TFs (transcription factors) that are correlative with plant growth and anthocyanin accumulation were identified to be differentially expressed in the transgenic lines. It was found that some key genes involved in IAA (Auxin) and GA (Gibberellin) biosynthesis were downregulated in the transgenic lines, which might be correlated with the phenotype changes in roots. Moreover, the upregulation of plant growth regulation genes, such as UGT73C4 (zeatin), ARR15, GH3.5, ETR2, ERS2, APH4, and SAG113 might be responsible for massive leaf growth. In addition, transgenic lines shown high anthocyanin accumulation due to the upregulation of the (1) 3AT1 and (3) GSTF, particularly, GSTF12 genes in the flavonoid biosynthesis pathway. However, the TFs such as, CCoAMT, bHLH, WRKY, CYP, and other MYBs were also significantly upregulated in transgenic lines, which increased the content of anthocyanins in A. thaliana seedlings. In conclusion, a BAHD acyltransferase (TEA031065) was identified, which might play a vital role in tea growth and secondary metabolites regulation. This study increases our knowledge concerning the combined functionality of the tea BAHD acyltransferase gene (TEA031065).

Genome-wide identification of tea plant (Camellia sinensis) BAHD acyltransferases reveals their role in response to herbivorous pests

“…Moreover, in addition to different stress-associated hormone response elements, a large number of TF binding site elements were also identified, predicting that the functional performance of tea plant BAHDs may also be regulated by different TFsas has been found in previous studies. For example, overexpression of a tea plant BAHD gene in Arabidopsis resulted in significant accumulation of anthocyanin, while many TF genes, such as WRKY, bHLH, and MYB were also significantly upregulated in the transgenic lines [ 30 ]. In addition, our correlation analysis further revealed the presence of a large number of TFs coexpressed with different BAHDs under tea geometrids or tea green leafhoppers feeding.…”

“…However, to date, there has been little known about the BAHD family in tea plants. In a previous study, 21 BAHD members were identified from the tea plant draft genome, and ectopic overexpression analysis of one member (TEA031065) showed a dramatic increase in growth and anthocyanin content in the transgenic lines [ 30 ]. In another study, we found that the expression of the CsCHAT1 gene was upregulated several hundred-fold after tea plants were subjected to feeding by tea green leafhoppers [ 31 ].…”

Meloidogyne enterolobiiMeMSP1 effector targets the glutathione‐S‐transferase phi GSTF family in Arabidopsis to manipulate host metabolism and promote nematode parasitism

“…This group of specialised plant metabolites includes > 10 000 different compounds. Plant GSTFs are involved in flavonoid biosynthesis (Shao et al ., 2022; Aktar et al ., 2022). Our understanding of the functions of almost all these substances remains poor, but there is increasing evidence to suggest a role for flavonoids in plant stress resistance (Sugiyama & Yazaki, 2014).…”

From a different angle: genetic diversity underlies differentiation of waterlogging-induced epinasty in tomato

“…The HCT clade belongs to a larger family of BAHD acyltransferases, involved in the specialized metabolism, including the production of phenolic compounds such as anthocyanin and suberin in roots ( Gou et al., 2009 ; Bontpart et al., 2015 ; Molina and Kosma, 2015 ). In tea ( Camellia sinensis ), overexpression of one of these BAHD genes affects not only the specialized metabolism, but also plant growth ( Aktar et al., 2022 ). How and if this HCT gene aids tomato plants in waterlogging resilience remains to be investigated.…”