Phytohormones and candidate genes synergistically regulate fruitlet abscission in Areca catechu L.

BackgroundThe fruit population of most plants is under the control of a process named physiological drop to selectively abort some developing fruitlets. However, frequent fruitlet abscission severely restricts the yield of Areca catechu. To reveal the physiological and molecular variations in this process, we detected the variation of phytohormone levels in abscised and non-abscised fruitlets in A. catechu.ResultsThe levels of gibberellin acid, jasmonic acid, salicylic acid, abscisic acid and zeatin were elevated, while the indole-3-acetic acid and indole-3-carboxaldehyde levels were declined in the about-to-abscise part (AB) of abscission zone (AZ) compared to the non-abscised part (CK). Then the differentially expressed genes (DEGs) between AB and CK were screened based on transcriptome data. DEGs involved in phytohormone synthesis, response and transportation were identified as key genes. Genes related to cell wall biosynthesis, degradation, loosening and modification, and critical processes during fruit abscission were identified as role players. In addition, genes encoding transcription factors, such as NAC, ERF, WRKY, MADS and Zinc Finger proteins, showed differentially expressed patterns between AB and CK, were also identified as candidates.ConclusionsThese results unraveled a phytohormone signaling cross talk and key genes involved in the fruitlet abscission process in A. catechu. This study not only provides a theoretical basis for fruitlet abscission in A. catechu, but also identified many candidate genes or potential molecular markers for further breeding of fruit trees.

Automated summary

In this study, the physiological and molecular variations in the fruit abscission process of Areca catechu were investigated. The levels of various phytohormones were found to change during the abscission process, and key genes involved in phytohormone synthesis, response, and transportation were identified. This study provides important insights into fruitlet abscission in A. catechu and identifies potential candidate genes or molecular markers for further fruit tree breeding.