The Putative Role of the NAC Transcription Factor EjNACL47 in Cell Enlargement of Loquat (Eriobotrya japonica Lindl.)

Abstract

NAC transcription factors (TFs) are plant-specific TFs that play essential roles in plant development; however, the function of NAC TFs in loquat development remains unknown. The natural triploid loquat (Eriobotrya japonica Lindl.), Longquan No.1. B355, has larger organs than its corresponding diploid loquat (B2). Here, we cloned an NAC-like TF (EjNACL47 (NAC-like 47)) from the cDNA of triploid loquat B355 flowers. EjNACL47 has a conserved domain of NAC TFs and is homologous to AtNAC47. Transient expression in tobacco leaves revealed that EjNACL47 localized to the nucleus, and yeast-two-hybrid screening confirmed that the C-terminus displayed transcriptional activity. Interestingly, real-time qRT-PCR indicated that the expression levels of EjNACL47 in leaves and flower organs in triploid loquat (B355) were higher than those in diploid loquat (B2), implying that EjNACL47 might be associated with the larger organ size in B355. Moreover, Arabidopsis lines ectopically expressing EjNACL47 presented obviously larger leaves, flowers, and siliques than the wild-type variant, suggesting that EjNACL47 plays a positive role in Arabidopsis organ enlargement. These results offer insight into the molecular mechanism of NAC TFs involved in regulating organ size in loquat.