Open AccessA sorghum NAC gene is associated with variation in biomass properties and yield potential
Author(s) -
Xia Jingnu,
Zhao Yunjun,
Burks Payne,
Pauly Markus,
Brown Patrick J.
Publication year - 2018
Publication title -
plant direct
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.211
H-Index - 11
ISSN - 2475-4455
DOI - 10.1002/pld3.70
Subject(s) - sorghum , biology , locus (genetics) , stalk , candidate gene , quantitative trait locus , gene , sweet sorghum , genetic variation , allele , genetics , sugar , botany , horticulture , agronomy , food science
Sorghum bicolor is a C 4 grass widely cultivated for grain, forage, sugar, and biomass. The sorghum Dry Stalk (D) locus controls a qualitative difference between juicy green (dd) and dry white (D‐) stalks and midribs, and co‐localizes with a quantitative trait locus for sugar yield. Here, we apply fine‐mapping and genome‐wide association study ( GWAS ) to identify a candidate gene underlying D , and use nearly isogenic lines (NILs) to characterize the transcriptional, compositional, and agronomic effects of variation at the D locus. The D locus was fine‐mapped to a 36 kb interval containing four genes. One of these genes is a NAC transcription factor that contains a stop codon in the NAC domain in the recessive (dd) parent. Allelic variation at D affects grain yield, sugar yield, and biomass composition in NILs. Green midrib ( dd) NIL s show reductions in lignin in stalk tissue and produce higher sugar and grain yields under well‐watered field conditions. Increased yield potential in dd NIL s is associated with increased stalk mass and moisture, higher biomass digestibility, and an extended period of grain filling. Transcriptome profiling of midrib tissue at the 4–6 leaf stages, when NIL s first become phenotypically distinct, reveals that dd NIL s have increased expression of a miniature zinc finger ( MIF ) gene. MIF genes dimerize with and suppress zinc finger homeodomain ( ZF ‐ HD ) transcription factors, and a ZF ‐ HD gene is associated with midrib color variation in a GWAS analysis across 1,694 diverse sorghum inbreds. A premature stop codon in a NAC gene is the most likely candidate polymorphism underlying the sorghum D locus. More detailed understanding of the sorghum D locus could help improve agronomic potential in cereals.