Phylogenomic analysis of phenylalanine ammonia-lyase (PAL) multigene family and their differential expression analysis in wheat (Triticum aestivum L.) suggested their roles during different stress responses

Abstract

Phenylalanine ammonia-lyase (PAL) is a key enzyme in the phenylalanine metabolism pathway and plays an important role in plant growth and stress response. It has been widely reported in plants, but less studied in wheat. In this study, 54 PAL genes were identified in the wheat genome. Based on phylogenetic analysis, the 54 TaPAL genes were divided into four groups (I, II, III, and IV). Then, the expression levels of TaPALs under biotic stresses were analyzed by transcriptome data analysis. The results showed that 31 genes were up-regulated and one gene was down-regulated after inoculation with Fusarium graminearum, 11 genes were up-regulated and 14 genes were down-regulated after inoculation with Puccinia striiformis, and 32 up-regulated and three down-regulated genes after inoculation with powdery mildew. The expression patterns of the five TaPALs were further analyzed by qRT-PCR. After inoculation with F. graminearum, the expression levels of five TaPALs were up-regulated. However, the TaPALs (expect TaPAL49) were down-regulated when inoculated with P. striiformis. Finally, the functions of TaPAL32 and TaPAL42 in resistance of wheat to the stripe rust were further analyzed by virus induced gene silencing (VIGS) assays. The results showed that the disease severity of TaPAL32 and TaPAL42 silenced plants was higher than that of control plants at 14 days after inoculation. It indicated that these two genes played a positive role in wheat stripe rust resistance. This study provided new evidence support for the functional study of PAL genes in wheat, and provided potential application value for the breeding of wheat resistant varieties.

Modulation of lignin biosynthesis for drought tolerance in plants

“…Monolignol biosynthesis begins with the deamination of phenylalanine through phenylalanine ammonia-lyase (PAL), producing cinnamic acid. Due to its critical role in phenylpropanoid biosynthesis, function of PAL has been extensively studied in various plants ( Wanner et al., 1995 ; Zhu et al., 1995 ; Chang et al., 2008 ; Zhan et al., 2022 ). In Arabidopsis ( Arabidopsis thaliana ), mutation of PAL1 and PAL2 led to a significant decrease in phenylpropanoids and lignin ( Rohde et al., 2004 ).…”

Transcriptomic insights into the genetic basis of improved Fusarium crown rot resistance during wheat allohexaploidization

“…variabilis [34]. In wheat, silencing of TaPAL32 and TaPAL42 reduces the resistance of wheat to stripe rust [35]. In the transcriptome analyses in the present study, cinnamic acid biosynthesis (GO:0009800) and L-phenylalanine catabolic (GO:0006559) processes were highlighted, both in SHWs and their parents, following FCR infection.…”

Comparative analysis of Fusarium crown rot resistance in synthetic hexaploid wheats and their parental genotypes

“…As an entry-point enzyme in the phenylpropanoid biosynthesis pathway, PAL converts phenylalanine to trans-cinnamic acid and free ammonia, thereby playing an important role in lignin and salicylic acid biosynthesis. Many studies have shown that PAL acts as a positive regulator of resistance to various plant biotic stresses [ 30 – 36 ]. In the transcriptome analyses in the present study, cinnamic acid biosynthesis (GO:0009800) and L-phenylalanine catabolic (GO:0006559) processes were significantly enriched both in SHWs and their parents following FCR infection.…”