Identification and Functional Analysis of the Caffeic Acid O-Methyltransferase (COMT) Gene Family in Rice (Oryza sativa L.)

Abstract

Caffeic acid O-methyltransferase (COMT) is one of the core enzymes involved in lignin synthesis. However, there is no systematic study on the rice COMT gene family. We identified 33 COMT genes containing the methyltransferase-2 domain in the rice genome using bioinformatic methods and divided them into Group I (a and b) and Group II. Motifs, conserved domains, gene structure and SNPs density are related to the classification of OsCOMTs. The tandem phenomenon plays a key role in the expansion of OsCOMTs. The expression levels of fourteen and thirteen OsCOMTs increased or decreased under salt stress and drought stress, respectively. OsCOMTs showed higher expression levels in the stem. The lignin content of rice was measured in five stages; combined with the expression analysis of OsCOMTs and multiple sequence alignment, we found that OsCOMT8, OsCOMT9 and OsCOMT15 play a key role in the synthesis of lignin. Targeted miRNAs and gene ontology annotation revealed that OsCOMTs were involved in abiotic stress responses. Our study contributes to the analysis of the biological function of OsCOMTs, which may provide information for future rice breeding and editing of the rice genome.

Genetic and evolutionary dissection of melatonin response signaling facilitates the regulation of plant growth and stress responses

“…In rice, COMT exhibited functional diversity and conservation in regulating abiotic stress such as OsCOMT20/31 induced by salt; OsCOMT2/5/16/21 upregulated under drought condition; OsCOMT1-mediated Cd tolerance. 84,85 Consistent with this, 55 GmCOMT genes in soybeans showed differential functional patterns that GmCOMT19 expression increased under drought treatment, and GmCOMT29/34 decreased under the salt treatment. 86 Similarly, BnCOMT1/5/8 alleviated Al, Cd, and drought damage, but BnCOMT4/6 displayed a diverse role.…”

“…The newly emerging COMT gained significantly higher ASMT activity to produce more melatonin for land plants coping with abiotic stress (Figure 2). In rice, COMT exhibited functional diversity and conservation in regulating abiotic stress such as OsCOMT20/31 induced by salt; OsCOMT2/5/16/21 upregulated under drought condition; OsCOMT1 ‐mediated Cd tolerance 84,85 . Consistent with this, 55 GmCOMT genes in soybeans showed differential functional patterns that GmCOMT19 expression increased under drought treatment, and GmCOMT29/34 decreased under the salt treatment 86 .…”

“…Upregulated expression of OsCOMTs in rice stem and BnCOMT1 in oilseed rape stem indicated their responsible role in stem development. 85,88 Manipulation of PlCOMT1 expression showed a great effect on stem strength and S/G ratio. 125 The COMT RNAi rice seedlings were semi-dwarf phenotypes with erect leaves, while MzCOMT1 overexpressing exhibited improved seedling growth and higher chlorophyll content under continuous light stress.…”

“…COMT exhibited a significant role in the regulation of plant vegetable growth (Figure 2). Upregulated expression of OsCOMTs in rice stem and BnCOMT1 in oilseed rape stem indicated their responsible role in stem development 85,88 . Manipulation of PlCOMT1 expression showed a great effect on stem strength and S/G ratio 125 .…”

The regulation of plant cell wall organisation under salt stress

“…Among 33 identified genes, 5 and 4 OsCOMTs were up-and down-regulated under salt stress, respectively. A combined investigation of lignin content and expression analysis of COMT genes suggested that OsCOMT8, OsCOMT9, and OsCOMT15 as the key players in the synthesis of lignin (Liang et al, 2022).…”