A NAC transcription factor, EjNAC1, affects lignification of loquat fruit by regulating lignin

• Two EjNACs were isolated from loquat.
• EjNAC1 was responsive to temperature and related to postharvest fruit lignification.
• EjNAC1 regulated fruit lignification by trans-activating lignin biosynthesis genes.

Lignin is an important component of secondary cell walls, and its content influences the utilization of plant products for food and fiber. Loquat is a typical fruit accumulating lignin during postharvest low temperature storage. In this research, two EjNAC genes were isolated and designated as EjNAC1 and EjNAC2. Both EjNAC1 and EjNAC2 had transcriptional activity in yeast cells. The expression of EjNAC1 and EjNAC2 in lignin-rich stems was higher than in pulp. However, only EjNAC1 was induced in fruit by low temperature and inhibited by heat treatment (HT), which can alleviate lignification, while EjNAC2 expression was not correlated with fruit lignification. Further analysis indicated that EjNAC1 could trans-activate the gene promoters in loquat and Arabidopsis for genes in the lignin biosynthesis pathway. Transient over-expression of EjNAC1 in tobacco leaves resulted in accumulation of lignin and induction of expression of endogenous lignin biosynthesis genes. In conclusion, EjNAC1 was associated with fruit lignification by activating genes involved in lignin biosynthesis.