Fertility of Pedicellate Spikelets in Sorghum Is Controlled by a Jasmonic Acid Regulatory Module

• Published in: International journal of molecular sciences Vol. 20; no. 19; p. 4951
• Main Authors: Gladman, Nicholas, Jiao, Yinping, Lee, Young Koung, Zhang, Lifang, Chopra, Ratan, Regulski, Michael, Burow, Gloria, Hayes, Chad, Christensen, Shawn A, Dampanaboina, Lavanya, Chen, Junping, Burke, John, Ware, Doreen, Xin, Zhanguo
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 08-10-2019; MDPI
• Subjects: Amino Acid Sequence; Binding Sites; Biosynthesis; Corn; Crop yield; Crops; Cyclopentanes - metabolism; Cytochrome; Edible Grain; Fertility; Flowers; Gene expression; Gene Expression Profiling; Gene Expression Regulation, Plant; Genomes; Genomics; Genotype & phenotype; Infertility; Jasmonic acid; jasmonic acid signaling; Lipoxygenase; Liquid oxygen; Metabolic Networks and Pathways; Mutation; Ontology; Oxylipins - metabolism; Peptides; Phylogeny; Plant Development; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Principal components analysis; Promoter Regions, Genetic; Protein Binding; Seeds; Sorghum; Sorghum - classification; Sorghum - physiology; Sorghum bicolor; Transcription factors; Transcription Factors - metabolism; transcriptional regulators; plant development; jasmonic acid signaling; transcriptional regulators; gene expression
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms20194951

As in other cereal crops, the panicles of sorghum (
(L.) Moench) comprise two types of floral spikelets (grass flowers). Only sessile spikelets (SSs) are capable of producing viable grains, whereas pedicellate spikelets (PSs) cease development after initiation and eventually abort. Consequently, grain number per panicle (GNP) is lower than the total number of flowers produced per panicle. The mechanism underlying this differential fertility is not well understood. To investigate this issue, we isolated a series of ethyl methane sulfonate (EMS)-induced
(
) mutants that result in full spikelet fertility, effectively doubling GNP. Previously, we showed that MSD1 is a TCP (Teosinte branched/Cycloidea/PCF) transcription factor that regulates jasmonic acid (JA) biosynthesis, and ultimately floral sex organ development. Here, we show that
encodes a lipoxygenase (LOX) that catalyzes the first committed step of JA biosynthesis. Further, we demonstrate that MSD1 binds to the promoters of
and other JA pathway genes. Together, these results show that a JA-induced module regulates sorghum panicle development and spikelet fertility. The findings advance our understanding of inflorescence development and could lead to new strategies for increasing GNP and grain yield in sorghum and other cereal crops.