Identification and molecular characterization of an IDA-like gene from litchi, LcIDL1, whose ectopic expression promotes floral organ abscission in Arabidopsis.

Peiyuan Ying,Xuncheng Liu,Jianguo Li,Rui Xia,Minglei Zhao,Caiqin Li

doi:10.1038/srep37135

Abstract

Unexpected abscission of flowers or fruits is a major limiting factor for crop productivity. Key genes controlling abscission in plants, especially in popular fruit trees, are largely unknown. Here we identified a litchi (Litchi chinensis Sonn.) IDA-like (INFLORESCENCE DEFICIENT IN ABSCISSION-like) gene LcIDL1 as a potential key regulator of abscission. LcIDL1 encodes a peptide that shows the closest homology to Arabidopsis IDA, and is localized in cell membrane and cytoplasm. Real-time PCR analysis showed that the expression level of LcIDL1 accumulated gradually following flower abscission, and it was obviously induced by fruit abscission-promoting treatments. Transgenic plants expressing LcIDL1 in Arabidopsis revealed a role of LcIDL1 similar to IDA in promoting floral organ abscission. Moreover, ectopic expression of LcIDL1 in Arabidopsis activated the expression of abscission-related genes. Taken together, our findings provide evidence that LcIDL1 may act as a key regulator in control of abscission.

Highlights

PROTEIN KINASE (MAPK) cascade that acts to regulate downstream KNOX-like transcription factor BP/ KNAT1
In an effort to identify the components of fruit abscission in litchi, we screened for genes that were differentially expressed during abscission from a RNA-seq database
We showed that ida-2 pAtIDA:LcIDL1 transgenic lines ida-2 pAtIDA:LcIDL1-1 and ida-2 pAtIDA:LcIDL1-2 displayed the same floral organ abscission process as the wild-type, with the floral organs dropped at position 9 (Fig. 6C)

Summary

Introduction

PROTEIN KINASE (MAPK) cascade that acts to regulate downstream KNOX-like transcription factor BP/ KNAT1. The characterization of key regulators in control of abscission has been reported mainly in the model plants tomato and Arabidopsis; these factors are largely unknown in perennial woody plants, especially in important horticultural cultivated fruit crops, such as litchi. Genome-wide digital transcript analysis further revealed that a range of fruitlet abscission-related genes are regulated by ethylene and carbohydrate stress[36,37]. We identified three IDA-like genes in litchi, of which LcIDL1 shows the closest homology to Arabidopsis IDA and is found to be involved in litchi male flower and fruitlet abscission. Our data suggest that LcIDL1 may act as a key regulator in control of abscission

Methods

Results

Conclusion