The buffering capacity of stems: genetic architecture of nonstructural carbohydrates in cultivated Asian rice, Oryza sativa

Abstract

Summary Harnessing stem carbohydrate dynamics in grasses offers an opportunity to help meet future demands for plant‐based food, fiber and fuel production, but requires a greater understanding of the genetic controls that govern the synthesis, interconversion and transport of such energy reserves.We map out a blueprint of the genetic architecture of rice (Oryza sativa) stem nonstructural carbohydrates (NSC) at two critical developmental time‐points using a subpopulation‐specific genome‐wide association approach on two diverse germplasm panels followed by quantitative trait loci (QTL) mapping in a biparental population.Overall, 26 QTL are identified; three are detected in multiple panels and are associated with starch‐at‐maturity, sucrose‐at‐maturity and NSC‐at‐heading. They tag OsHXK6 (rice hexokinase), ISA2 (rice isoamylase) and a tandem array of sugar transporters.This study provides the foundation for more in‐depth molecular investigation to validate candidate genes underlying rice stem NSC and informs future comparative studies in other agronomically vital grass species.

An imputation platform to enhance integration of rice genetic resources

“…To see whether rice imputation using the parameters selected in this study for imputing array data was generalizable for sparse data sets, we selected a subset of 16 tropical japonica varieties from a previously published GBS data set consisting of 38,618 SNPs 35 . These 16 varieties were chosen because they fulfilled two criteria: (1) they were not part of RICE-RP and (2) they were part of an independent resequencing effort 15 .…”

“…All gene annotations used here were taken from the MSUv7 genome assembly ( http://rice.plantbiology.msu.edu/ ). Local LD associated with significant SNPs was determined following the method described previously 35 .…”

Characterization of sugar metabolism in the stem of Tachisuzuka, a whole-crop silage rice cultivar with high sugar content in the stem

“…A recent genome-wide association study on carbohydrate content in rice stems using diverse germplasm panels of tropical japonica rice showed that ISA2 genotype is associated with sucrose content in the stem at harvest (Wang et al, 2017). In the present study, the expression UGP1 SPS2 AGPL1 SUT2 UGP3 SPS6 AGPL2 SUT4 FK1/FKII SPS8 AGPL3 TPT1 FK2/FKI SPS11 AGPS1 TPT2 FK3 SPP1 AGPS2 GPT1 HXK2 SPP2 SSI G PT2 HXK3 SPP5 SSIIb G PT2-3 HXK4 cFBP1 S it is unknown whether TMT1 can transport sucrose (Cho et al, 2010).…”

Potassium deficiency aggravates yield loss in rice by restricting the translocation of non‐structural carbohydrates under Sarocladium oryzae infection condition

“…S1A, Supporting information), whereas the FLS is a temporal sink to store NSC before anthesis and also acts as a ‘transfer station’ of non‐structural carbohydrates (NSC) translocation from flag leaf (FL) to panicles during grain‐filling (Chen and Wang ). To improve grain yield and buffering capacity of plants under stress conditions, NSC exportation from source organs to sink organs (grains) is crucial (Pan et al , Wang et al ). Prior study demonstrated that the long‐distance translocation of NSC (mainly in the form of sucrose) in rice utilizes an apoplasmic and symplasmic phloem loading process, both requiring a stabilized cell membrane (Braun et al ).…”