Abstract
BackgroundPlant architecture is a critical factor that affects planting density and, consequently, grain yield in maize. The genes or loci that determine organ size are the key regulators of plant architecture. Thus, understanding the genetic and molecular mechanisms of organ size will inform the use of a molecular manipulation approach to improve maize plant architecture and grain yield.ResultsA total of 18 unique quantitative trait loci (QTLs) were identified for 11 agronomic traits in the F2 and F2:3 segregating populations derived from a cross between a double haploid line with a small plant architecture (MT03-1) and an inbred line with a large plant architecture (LEE-12). Subsequently, we showed that one QTL, qLW10, for multiple agronomic traits that relate to plant organ size reflects allelic variation in ZmCSLD1, which encodes a cellulose synthase-like D protein. ZmCSLD1 was localized to the trans-Golgi and was highly expressed in the rapidly growing regions. The loss of ZmCSLD1 function decreased cell division, which resulted in smaller organs with fewer cell numbers and, in turn, pleiotropic effects on multiple agronomic traits. In addition, intragenic complementation was investigated for two Zmcsld1 alleles with nonsynonymous SNPs in different functional domains, and the mechanism of this complementation was determined to be through homodimeric interactions.ConclusionsThrough positional cloning by using two populations and allelism tests, qLW10 for organ size was resolved to be a cellulose synthase-like D family gene, ZmCSLD1. ZmCSLD1 has pleiotropic effects on multiple agronomic traits that alter plant organ size by changing the process of cell division. These findings provide new insight into the regulatory mechanism that underlies plant organ development.
Highlights
Plant architecture is a critical factor that affects planting density and, grain yield in maize
To investigate the genetic basis of these traits, Quantitative trait locus (QTL) mapping was performed for the 11 measured traits by using a genetic map of 1833.66 cM (Additional file 1: Tables S1; Additional file 2: Tables S2), and a total of 19 and 25 QTLs were detected in the F2 and F2:3 populations, respectively (Fig. 1a; Additional file 3: Table S3)
These QTLs were distributed in 18 genomic regions across 8 of the 10 chromosomes, except for chromosomes 6 and 9, and each QTL explained 3.27 to 75.05% of the phenotypic variation
Summary
Plant architecture is a critical factor that affects planting density and, grain yield in maize. The genes or loci that determine organ size are the key regulators of plant architecture. Understanding the genetic and molecular mechanisms of organ size will inform the use of a molecular manipulation approach to improve maize plant architecture and grain yield. Plant architecture is a result of many trait interactions during plant development and growth, and is a critical factor that affects plant density and, grain yield. Maize plant architecture includes plant height (PH), leaf number (LN), leaf angle (LA), leaf area, and tassel traits. The genetic architecture of organ size has been well studied in maize by using different genetic populations [6,7,8,9,10,11]. A nested association mapping (NAM) population, which contained ~ 5,000 recombinant inbred lines and was developed by crossing 25 diverse lines to B73, was
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