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Article|01 Aug 2018|OPEN
Aberrant seed development in Litchi chinensis is associated with the impaired expression of cell wall invertase genes
Jieqiong Zhang1,2,3, Zichen Wu2, Fuchu Hu1,2,4, Lian Liu2, Xuming Huang2, Jietang Zhao1,2, & Huicong Wang2,5,
1State Key Laboratory for Conservation and Utilization of Subtropical Agrobioresources, College of Horticulture, South China Agricultural University, Guangzhou, China
2Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
3Present address: Shanghai Center for Plant Stress Biology (PSC), Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, China
4Key laboratory of tropical fruit tree biology of Hainan Province, Hainan Academy of Agricultural Science, Haikou 571100, China
5Department of Life Sciences and Technology, Yangtze Normal University, Chongqing, China

Horticulture Research 5,
Article number: 39 (2018)
doi: 10.1038/hortres.2018.39
Views: 574

Received: 11 Dec 2017
Revised: 05 Apr 2018
Accepted: 15 Apr 2018
Published online: 01 Aug 2018

Abstract

Cell wall invertase (CWIN) are known to play important roles in seed development. However, most reports to date have focused on a single gene family member, and have mainly investigated CWIN functions during the filling stage of seed development. In this study, we found significant lower levels of CWIN protein and activity associated with seed abortion in the Litchi chinensis cultivar “Nuomici.” We identified five litchi CWIN genes and observed that the expression of LcCWIN5 was limited to the flower tissues and decreased sharply with fruit development. Silencing of LcCWIN5 expression before 28 DAA (cell division stage) resulted in perturbed liquid endosperm development, smaller seeds, and higher seed abortion rate, while silencing after 28 DAA (filling stage) had no effect on seed development. In contrast, LcCWIN2 was mostly expressed in the funicle and seed coat, and increased with fruit development. Decreased LcCWIN2 expression and CWIN activity during early seed filling coincided with smaller seeds in the cultivar “Feizixiao.” Silencing of LcCWIN2 caused a reduction in the seed size without inducing seed abortion. We propose that CWIN activity in seed maternal tissues during cell division stage is likely due to LcCWIN5 expression, which regulates early seed development. On the other hand, CWIN activity during the filling stage is due to the expression of LcCWIN2, which may promote carbon import by creating a sucrose gradient. Comparable LcCWIN5 expression, but much lower CWIN activity, detected in the funicle of “Nuomici” is consistent with post-translational regulation.