Genome-Wide Analysis and Expression Profiling of the SUC and SWEET Gene Families of Sucrose Transporters in Oilseed Rape (Brassica napus L.).

Hongju Jian,Liezhao Liu,Kun Lu,Aoxiang Zhang,Bo Yang,Li Zhang,Tengyue Wang,Cunmin Qu,Jiana Li,Jia Wang

doi:10.3389/fpls.2016.01464

Abstract

Sucrose is the principal transported product of photosynthesis from source leaves to sink organs. SUTs/SUCs (sucrose transporters or sucrose carriers) and SWEETs (Sugars Will Eventually be Exported Transporters) play significant central roles in phloem loading and unloading. SUTs/SUCs and SWEETs are key players in sucrose translocation and are associated with crop yields. The SUT/SUC and SWEET genes have been characterized in several plant species, but a comprehensive analysis of these two gene families in oilseed rape has not yet been reported. In our study, 22 and 68 members of the SUT/SUCs and SWEET gene families, respectively, were identified in the oilseed rape (Brassica napus) genome through homology searches. An analysis of the chromosomal distribution, phylogenetic relationships, gene structures, motifs and the cis-acting regulatory elements in the promoters of BnSUC and BnSWEET genes were analyzed. Furthermore, we examined the expression of the 18 BnSUC and 16 BnSWEET genes in different tissues of “ZS11” and the expression of 9 BnSUC and 7 BnSWEET genes in “ZS11” under various conditions, including biotic stress (Sclerotinia sclerotiorum), abiotic stresses (drought, salt and heat), and hormone treatments (abscisic acid, auxin, cytokinin, brassinolide, gibberellin, and salicylic acid). In conclusion, our study provides the first comprehensive analysis of the oilseed rape SUC and SWEET gene families. Information regarding the phylogenetic relationships, gene structure and expression profiles of the SUC and SWEET genes in the different tissues of oilseed rape helps to identify candidates with potential roles in specific developmental processes. Our study advances our understanding of the important roles of sucrose transport in oilseed rape.

Highlights

Sucrose is the principal transported product of photosynthesis from source leaves to sink organs (Peng et al, 2014)
The results indicated that BnSUC1C is predominantly expressed in the later developmental stage of the anther
Sixty-eight, 26 and 16 SWEET proteins were identified in the B. napus, B. rapa, and B. oleracea genomes, respectively

Summary

Introduction

Sucrose is the principal transported product of photosynthesis from source leaves to sink organs (Peng et al, 2014). Previous studies have revealed that SUCs are located in the plasma membranes of the sieve element and companion cells and are expressed in various tissues from source leaves to sink tissues (Aoki et al, 2004; Sauer et al, 2004; Sivitz et al, 2005; Liesche et al, 2008; Tang et al, 2010). AtSUC2 is the best-characterized type I SUC, and mutational analysis has shown that SUCs are responsible for restraining plant growth and pollen germination (Gottwald et al, 2000; Sivitz et al, 2008; Srivastava et al, 2009). Antisense transformation experiments have revealed that SUCs are responsible for the retardation of sucrose translocation, fruit size reduction, and reduced fertility in tomato (Riesmeier et al, 1994; Hackel et al, 2006)

Methods

Results

Conclusion