Genome-wide association study reveals the genetic architecture of root hair length in maize

Abstract

Background Root hair, a special type of tubular-shaped cell, outgrows from root epidermal cell and plays important roles in the acquisition of nutrients and water, as well as interactions with biotic and abiotic stress. Although many genes involved in root hair development have been identified, genetic basis of natural variation in root hair growth has never been explored. Results Here, we utilized a maize association panel including 281 inbred lines with tropical, subtropical, and temperate origins to decipher the phenotypic diversity and genetic basis of root hair length. We demonstrated significant associations of root hair length with many metabolic pathways and other agronomic traits. Combining root hair phenotypes with 1.25 million single nucleotide polymorphisms (SNPs) via genome-wide association study (GWAS) revealed several candidate genes implicated in cellular signaling, polar growth, disease resistance and various metabolic pathways. Conclusions These results illustrate the genetic basis of root hair length in maize, offering a list of candidate genes predictably contributing to root hair growth, which are invaluable resource for the future functional investigation.

Natural polymorphisms in ZmIRX15A affect water‐use efficiency by modulating stomatal density in maize

“…and originated in southwestern Mexico, and ever since has been cultivated and subjected to extensive selection for traits suited to numerous climatic regions including temperate zones (Doebley et al ., 2006; Ranere et al ., 2009). A large number of studies have shown that population structure is significantly associated with differences in various morphological characteristics of maize (Castelletti et al ., 2020; Liu et al ., 2021; Sun et al ., 2022b; Wang et al ., 2016b), but few studies have addressed the evolutionary variation in SD, which ultimately manifests as geographic phenotypic differences. In our study, maize MIXED and TEM germplasm exhibited a higher SD than TST germplasm, implying that the adaption of maize from tropical to temperate regions was probably accompanied by an increase in SD (Figure 1B).…”

Genomic insight into changes of root architecture under drought stress in maize

“…For example, two drought‐tolerant genes ZmVPP1 and ZmTIP1 discovered by GWAS, ZmVPP1 improved drought tolerance of Arabidopsis and maize by increased lateral root number and root biomass (Wang et al, 2016), and ZmTIP1 enhanced drought tolerance of maize through regulating the length of root hairs (Zhang et al, 2020). Several GWAS experiments have been performed for root traits at different growth stages and under different water treatments in maize, including root traits under hydroponic or soil conditions at seedling stage (Liu et al, 2021; Moussa et al, 2021; Pace et al, 2015a), under normal field conditions at maturation stage (Wang et al, 2021; Wu et al, 2022; Zheng et al, 2020), and under both drought stress and normal conditions at reproductive stage (Schneider et al, 2020; Zaidi et al, 2016). Although GWAS of maize root traits under drought stress or WW conditions have been attempted, few causal genes have been identified and elucidated for root system related to traits with maize drought tolerance.…”