title: A single point mutation in Ms44 results in dominant male sterility and improves nitrogen use efficiency in maize.
abstract: Application of nitrogen fertilizer in the past 50 years has resulted in significant increases in crop yields. However, loss of nitrogen from crop fields has been associated with negative impacts on the environment. Developing maize hybrids with improved nitrogen use efficiency is a cost-effective strategy for increasing yield sustainably. We report that a dominant male-sterile mutant Ms44 encodes a lipid transfer protein which is expressed specifically in the tapetum. A single amino acid change from alanine to threonine at the signal peptide cleavage site of the Ms44 protein abolished protein processing and impeded the secretion of protein from tapetal cells into the locule, resulting in dominant male sterility. While the total nitrogen (N) content in plants was not changed, Ms44 male-sterile plants reduced tassel growth and improved ear growth by partitioning more nitrogen to the ear, resulting in a 9.6% increase in kernel number. Hybrids carrying the Ms44 allele demonstrated a 4%-8.5% yield advantage when N is limiting, 1.7% yield advantage under drought and 0.9% yield advantage under optimal growth conditions relative to the yield of wild type. Furthermore, we have developed an Ms44 maintainer line for fertility restoration, male-sterile inbred seed increase and hybrid seed production. This study reveals that protein secretion from the tapetum into the locule is critical for pollen development and demonstrates that a reduction in competition between tassel and ear by male sterility improves grain yield under low-nitrogen conditions in maize.
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Tim
authors.initials: T
authors.lastname: Fox
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: DeBruin
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Kristin
authors.initials: K
authors.lastname: Haug Collet
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Trimnell
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Clapp
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: April
authors.initials: A
authors.lastname: Leonard
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Bailin
authors.initials: B
authors.lastname: Li
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Scolaro
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Collinson
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Glassman
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Miller
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Jeff
authors.initials: J
authors.lastname: Schussler
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Dennis
authors.initials: D
authors.lastname: Dolan
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Lu
authors.initials: L
authors.lastname: Liu
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Carla
authors.initials: C
authors.lastname: Gho
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Albertsen
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Dale
authors.initials: D
authors.lastname: Loussaert
authors.affiliation: DuPont Pioneer, Johnston, IA, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Shen
mesh_terms: D009584:Nitrogen / Q000378:metabolism; D051479:Plant Infertility / Q000235:genetics* / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics*; D017354:Point Mutation / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
chemical_list: D010940:Plant Proteins; D009584:Nitrogen
keywords: 
  Ms44
  ; 
  NUE
  ; grain yield; lipid transfer protein; maize; male sterility