Development and identification of three functional markers associated with starch content in lotus (Nelumbo nucifera)

Teng Cheng,Zhongli Hu,Jiangdong Liu,Jianxiong Wang,Xingfei Zheng,Xingwen Zheng,Keqiang Xie,Ying Diao,Surong Jin

doi:10.1038/s41598-020-60736-6

Teng Cheng, Zhongli Hu + Show 7 more

Open Access

https://doi.org/10.1038/s41598-020-60736-6

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Abstract

It have been significantly demonstrated that Hexokinase (HXK), Granule-bound starch synthase (GBSS) and ADP-glucose pyrophosphorylase (AGPase) are three critical enzymes in the starch biosynthetic pathway and are related to starch (amylose, amylopectin and total starch) content in lotus. It is important to develop functional markers in marker-assisted selection of lotus breeding. So far there have been few reports about lotus functional markers. In this study, based on insertion-deletions (INDELs) and single-nucleotide polymorphisms (SNPs), we developed three functional markers, FMHXK-E1, FMGBSS-I8 and FMAGPL-I1. FMHXK-E1 was developed based on polymorphisms of two haplotypes of NnHXK. 26 lotus cultivars that the 320-bp fragment presented in NnHXK had a lower content of amylose and a higher content of amylopectin. FMGBSS-I8 was developed based on polymorphisms of two haplotypes of NnGBSS. The group containing 32 lotus cultivars with the 210-bp fragment had less amylose content and more amylopectin content. FMAGPL-I1 was developed based on polymorphisms of two haplotypes of NnAGPL (ADP-glucose pyrophosphorylase large subunit gene). The group containing 40 lotus cultivars with the 362-bp fragment had less amylopectin, total starch content and more amylose content. According to the study, FMHXK-E1, FMGBSS-I8 and FMAGPL-I1 are closely related to lotus starch content. It could be provided research basis for molecular assisted selection of lotus starch content improve breeding efficiency.

Highlights

Lotus (Nelumbo nucifera Gaertn), a perennial aquatic herb, is one of the oldest dicotyledonous plants[1], which originated and has been widely grown in southern China for thousands of years[2]
It was presented by Excel analysis that the amylose content is lower and the amylopectin content is higher of 26 lotus cultivars with the 320-bp fragment of NnHXK, and the amylose content is higher and the amylopectin content is lower of the another 20 lotus cultivars without the 320-bp fragment of NnHXK
The functional marker was developed and named FMHXK-E1 according to the gene HXK and primer

Summary

Introduction

Lotus (Nelumbo nucifera Gaertn), a perennial aquatic herb, is one of the oldest dicotyledonous plants[1], which originated and has been widely grown in southern China for thousands of years[2]. Starch can be divided into amylose and amylopectin in plant[4]. Up to now it is possible to develop markers from genes that have a putative function which is referred to as ‘functional markers’ (FMs)[8]. Traditional SSR and ISSR analysis of genetic diversity have been used in lotus cultivars[14,15,16], functional markers associated with starch content have not been developed and applied in lotus cultivars. It is a critical step towards selecting suitable lotus cultivars to develop functional markers on the identification of amylose, amylopectin and total starch content. Numerous studies showed that granule-bound starch synthase was encoded by the GBSS gene, which catalyzes amylose synthesis[18,19,20]. Identifying genes that control starch content could contribute to explore molecular markers about starch content

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