Journal Article

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

Christensen, Shawn A., Chopra, Ratan, Dampanaboina, Lavanya, Ware, Doreen, Gladman, Nicholas, Zhang, Lifang, Chen, Junping, Lee, Young Koung, Jiao, Yinping, Regulski, Michael, Hayes, Chad, Burke, John, Burow, Gloria, Xin, Zhanguo

2019

Overview

As in other cereal crops, the panicles of sorghum (Sorghum bicolor (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 multiseeded (msd) 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 MSD2 encodes a lipoxygenase (LOX) that catalyzes the first committed step of JA biosynthesis. Further, we demonstrate that MSD1 binds to the promoters of MSD2 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.

• Publisher: MDPI AG,MDPI
• Subject: Amino Acid Sequence / Binding Sites / Biosynthesis / Corn / Cyclopentanes - metabolism / Cytochrome / Edible Grain / Fertility / Gene expression / Gene Expression Profiling / Gene Expression Regulation, Plant / Genomes / Genomics / Genotype & phenotype / Infertility / 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 / Transcription factors / Transcription Factors - metabolism