Natural Variation atsympathy for the liguleControls Penetrance of the SemidominantLiguleless narrow-RMutation inZea mays

Abstract

Leaf architecture determines plant structural integrity, light harvesting, and economic considerations such as plant density. Ligules, junctions at the leaf sheath and blade in grasses, protect stalks from environmental stresses and, in conjunction with auricles, controls leaf angle. Previous studies in mutants have recessive liguleless mutants (lg1 and lg2) and dominant mutations in knotted1-like homeobox genes (Lg3-O, Lg4, and Kn1) involved in ligule development. Recently, a new semidominant liguleless mutant, Liguleless narrow (Lgn-R), has been characterized in maize that affects ligule and auricle development and results in a narrow leaf phenotype. We show that quantitative genetic variation affects penetrance of Lgn-R. To examine the genetic architecture underlying Lgn-R expressivity, crosses between Lgn-R/+ mutants in a B73 background and intermated B73 x Mo17 recombinant inbred lines were evaluated in multiple years and locations. A single main-effect quantitative trait locus (QTL) on chromosome 1 (sympathy for the ligule; sol) was discovered with a Mo17-contributed allele that suppressed Lgn-R mutant phenotypes. This QTL has a genetic-interaction with a locus on chromosome 7 (lucifer; lcf) for which the B73-contributed allele increases the ability of the solMo17 allele to suppress Lgn-R. Neither of the genetic intervals likely to contain sol or lcf overlap with any current liguleless genes nor with previously identified genome-wide association QTL connected to leaf architecture. Analysis of phenotypes across environments further identified a genotype by enviroment interaction determining the strength of the sol x lcf interaction.

AVery Oil Yellow1modifier of theOil Yellow1-N1989allele uncovers a cryptic phenotypic impact of cis-regulatory variation in maize

“…Thus, the Oy1-N1989 mutant allele can sensitize maize plants to 775 variation in MgChl and expose a phenotypic consequence for genetic variants that are 776 otherwise invisible. Similar methodology has been adopted previously in maize to gain the 777 genetic understanding of various traits (Chintamanani et al 2010;Olukolu et al 2013Olukolu et al , 778 2014Buescher et al 2014). Employing a mutant allele as a reporter to screen for effects 779 of natural variants is a simple and efficient technique to detect standing variation in a 780 specific biological process.…”

“…Olukolu et al 2013Olukolu et al , 2014Olukolu et al , 2016 and plant development(Buescher et al 2014), among…”

The Second Site Modifier, Sympathy for the ligule, Encodes a Homolog of Arabidopsis ENHANCED DISEASE RESISTANCE4 and Rescues the Liguleless narrow Maize Mutant

“…The expressivity of the Lgn-R phenotype is backgrounddependent. While the phenotype is severe in B73, plant height, leaf width, and inflorescence and ligule development are all restored to near wild-type levels in Mo17 (Buescher et al, 2014).…”

“…To investigate the difference in expressivity between B73 and Mo17, we created NILs by first crossing Lgn-R to the IBM recombinant inbreds (Buescher et al, 2014) and then backcrossing the least severe Lgn-R individuals to B73 for a minimum of four generations. We refer to the Mo17 Sol locus as Sol-M and the B73 locus as Sol-B.…”

“…To investigate these background differences, we crossed Lgn-R in B73 to the intermated Mo17 3 B73 recombinant inbred lines (IBM lines; Lee et al, 2002) and conducted a quantitative trait locus (QTL) analysis. Sympathy for the ligule (Sol) was identified as a main effect QTL on chromosome 1 (Buescher et al, 2014). A genotype-by-environment (GxE) effect was discovered by growing the population in two different environments.…”