|JIAO, YINPING - Cold Spring Harbor Laboratory|
|Echevarria Laza, Haydee|
Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2019
Publication Date: 7/25/2019
Citation: Chen, J., Jiao, Y., Echevarria Laza, H.J., Payton, P.R., Ware, D., Xin, Z. 2019. Identification of the first nuclear male sterility gene (Male-sterile 9) in sorghum. The Plant Genome. 12. https://doi.org/10.3835/plantgenome2019.03.0020.
Interpretive Summary: Grain yields of sorghum germplasm have been stagnant for decades in the U.S. and use of improved sorghum hybrid varieties is thought to be one way of increasing sorghum grain yields. For self-fertilizing crops, such as sorghum, controllable male sterility is essential to produce hybrids. Utilizing nuclear male sterility (NMS) in a two-line breeding system can greatly improve hybrid breeding efficiency and increase heterozygosity of the hybrid, a criterion of high yielding hybrid. Although several male sterile lines due to mutations in nuclear genes have been reported in sorghum, no male sterile gene has been identified. ARS scientists from Lubbock, Texas, have isolated and characterized a novel sorghum male sterile mutant, ms9 and identified the first male sterile gene in sorghum as a PHD (Plant Homeotic Domain) transcription factor. Homologs of this PHD gene are known to control the male sterility in rice, maize and Arabidopsis. Identification of the male sterile mutant and its underlying gene provide a vital tool for breeders to control male sterility and develop efficient two-line breeding system in sorghum.
Technical Abstract: Nuclear male sterility (NMS) is important to understand microspore development and has the potential to develop two-line breeding system. Several NMS lines and mutants have been identified in sorghum [Sorghum bicolor (L.) Moench] previously but no male sterile gene has been reported. Here, we characterized a new NMS mutant, male sterile9 (ms9), which is distinct from all other reported NMS loci. The ms9 mutant is a stable NMS mutant under a variety of environmental conditions. The homozygous ms9 mutant produced normal ovary but small pale-colored anthers that contained no pollen grain. Using MutMap, we identified the Ms9 gene as a Plant Homeotic Domain (PHD)-finger transcription factor similar to Ms1 in Arabidopsis and Ptc1 in rice. To our knowledge, Ms9 is the first NMS gene identified in sorghum. The Ms9 gene and the ms9 mutant provide genetic tools to study pollen development to control male sterility in sorghum.