Waxy allele diversification in foxtail millet (Setaria italica) landraces of Taiwan

Shu-meng Kuo; Yu-ru Chen; Song-yu Yin; Qing-xiong Ba; Yuan-ching Tsai; Warren H. J. Kuo; Yann-rong Lin

doi:10.1371/journal.pone.0210025

Waxy allele diversification in foxtail millet (Setaria italica) landraces of Taiwan

Journal

PLOS ONE

Journal Volume

13

Journal Issue

12

Pages

e021002-5

Date Issued

2018-12

Date

2018-12

Author(s)

Shu-meng Kuo

Yu-ru Chen

Song-yu Yin

Qing-xiong Ba

Yuan-ching Tsai

Warren H. J. Kuo

Yann-rong Lin

DOI

10.1371/journal.pone.0210025

URI

https://scholars.tari.gov.tw/handle/123456789/1955

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0210025

Abstract

Foxtail millet (Setaria italica (L.) P. Beauv.), the second most cultivated millet species, is well adapted to diverse environments and remains an important cereal food and forage crop in arid and semiarid regions worldwide. A symbolic crop for indigenous Austronesian peoples, foxtail millet has been cultivated in Taiwan for more than 5,000 years, and landraces reflect diversifying selection for various food applications. A total of 124 accessions collected within Taiwan were assessed for Wx genotypes. Four identified Wx alleles, I, III, IV, and IX were caused by insertion of various transposable elements (TEs) and resulted in endosperm with non-waxy, low amylose content (AC), and waxy, respectively. A total of 16.9%, 4.0%, 49.2%, and 29.8% of accessions were classified as type I, III, IV, and IX, respectively; approximately half of the accessions belonged to the waxy type, indicating that glutinous grains were favored for making traditional food and wine. The TE insertion affected splicing efficiency rather than accuracy, leading to significantly reduced expression of wx in types III, IV, and IX, although their transcripts were the same as wild-type, type I. Consequently, the granule-bound starch synthase I (GBSSI) contents of the three mutated genotypes were relatively low, leading to waxy or low AC endosperm, and the Wx genotypes could explain 78% of variance in AC. The geographic distribution of Wx genotypes are associated with culinary preferences and migration routes of Taiwanese indigenous peoples-in particular, the genotype of landraces collected from Orchid Island was distinct from those from Taiwan Island. This information on the major gene regulating starch biosynthesis in foxtail millet endosperm can be applied to breeding programs for grain quality, and contributes to knowledge of Austronesian cultures.

Publisher

Public Library of Science

Type

journal article

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