PbLAC4-like, activated by PbMYB26, related to the degradation of anthocyanin during color fading in pear

Guangping Zhao,Chengquan Yang,Linyan Song,Rui Zhai,Junxing Song,Fengwang Ma,Fangxin Xiang,Shichao Zhang,Xieyu Li,Lingfei Xu,Zhigang Wang

doi:10.1186/s12870-021-03220-1

Guangping Zhao, Chengquan Yang + Show 9 more

Open Access

https://doi.org/10.1186/s12870-021-03220-1

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Abstract

BackgroundDecrease in anthocyanin content results in the loss of red color in leaves, petals and receptacles during development. The content of anthocyanin was affected by the biosynthesis and degradation of anthocyanin. Compared with the known detailed mechanism of anthocyanin biosynthesis, the degradation mechanism is not fully investigated. It is vital to study the degradation mechanism of anthocyanin in pear for promoting the accumulation of anthocyanin and inhibiting the red fading in pear.ResultsHere, we reported that laccase encoded by PbLAC4-like was associated with anthocyanin degradation in pear. The expression pattern of PbLAC4-like was negatively correlated with the content of anthocyanin during the color fading process of pear leaves, petals and receptacles. Phylogenetic analysis and sequence alignment revealed that PbLAC4-like played a vital role in anthocyanin degradation. Thus, the degradation of anthocyanin induced by PbLAC4-like was further verified by transient assays and prokaryotic expression. More than 80% of anthocyanin compounds were degraded by transiently over-expressed PbLAC4-like in pear fruitlet peel. The activity of crude enzyme to degrade anthocyanin in leaves at different stages was basically consistent with the expression of PbLAC4-like. The anthocyanin degradation ability of prokaryotic induced PbLAC4-like protein was also verified by enzyme activity assay. Besides, we also identified PbMYB26 as a positive regulator of PbLAC4-like. Yeast one-hybrid and dual luciferase assay results showed that PbMYB26 activated PbLAC4-like expression by directly binding to the PbLAC4-like promoter.ConclusionsTaken together, the PbLAC4-like activated by PbMYB26, was involved in the degradation of anthocyanin, resulting in the redness fading in different pear tissues.

Highlights

Decrease in anthocyanin content results in the loss of red color in leaves, petals and receptacles during development
UDP glucose: flavonoid 3-O-glucosyl transferase (UFGT) was identified as a key enzyme involved in anthocyanin biosynthesis [13]
COP1.1 and MYB120 were identified as inhibitory regulators of anthocyanin biosynthesis in pear [17, 18]. bHLH3, MYB88, MYB124, NAC52 and in apple [19,20,21], MYB75, MYB90, MYB113 and MYB114 in Arabidopsis thaliana [22,23,24] were shown to promote anthocyanin biosynthesis

Summary

Introduction

Decrease in anthocyanin content results in the loss of red color in leaves, petals and receptacles during development. The content of anthocyanin was affected by the biosynthesis and degradation of anthocyanin. UFGT was identified as a key enzyme involved in anthocyanin biosynthesis [13]. MYB10, MYB10b, ERF22, REVEILLE promoted the biosynthesis of anthocyanin by activating the expression of anthocyanin biosynthesis genes in pear [14,15,16]. COP1.1 and MYB120 were identified as inhibitory regulators of anthocyanin biosynthesis in pear [17, 18]. BHLH3, MYB88, MYB124, NAC52 and in apple [19,20,21], MYB75, MYB90, MYB113 and MYB114 in Arabidopsis thaliana [22,23,24] were shown to promote anthocyanin biosynthesis. MYB6 in apple [25] and MYB1 in Gerbera hybrid [26] were identified to inhibit anthocyanin biosynthesis

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