Abstract
Zinc (Zn) deficiency, a globally predominant micronutrient disorder in crops and humans, reduces crop yields and adversely impacts human health. Despite numerous studies on the physiological mechanisms underlying Zn deficiency tolerance, its genetic basis of molecular mechanism is still poorly understood. Thus, the Zn efficiency of 20 maize inbred lines was evaluated, and a quantitative trait locus (QTL) analysis was performed in the recombination inbred line population derived from the most Zn-efficient (Ye478) and Zn-inefficient inbred line (Wu312) to identify the candidate genes associated with Zn deficiency tolerance. On this basis, we analyzed the expression of ZmZIP1-ZmZIP8. Thirteen QTLs for the traits associated with Zn deficiency tolerance were detected, explaining 7.6–63.5% of the phenotypic variation. The genes responsible for Zn uptake and transport across membranes (ZmZIP3, ZmHMA3, ZmHMA4) were identified, which probably form a sophisticated network to regulate the uptake, translocation, and redistribution of Zn. Additionally, we identified the genes involved in the indole-3-acetic acid (IAA) biosynthesis (ZmIGPS) and auxin-dependent gene regulation (ZmIAA). Notably, a high upregulation of ZmZIP3 was found in the Zn-deficient root of Ye478, but not in that of Wu312. Additionally, ZmZIP4, ZmZIP5, and ZmZIP7 were up-regulated in the Zn-deficient roots of Ye478 and Wu312. Our findings provide a new insight into the genetic basis of Zn deficiency tolerance.
Highlights
Specialty section: This article was submitted toPlant Nutrition, a section of the journal Frontiers in Plant ScienceReceived: 10 July 2021 Accepted: 30 September 2021 Published: 15 November 2021Citation: Xu J, Wang X, Zhu H and Yu F (2021) Identification and Analysis of Zinc Efficiency-Associated Loci in Maize
The linear mixed effect function Imer from the lme4 package in R was fitted to each recombinant inbred line (RIL) to obtain the best linear unbiased prediction (BLUP) value for each trait: yi = μ + fi + ei + εi, where yi is the phenotypic value of individual i, μ is the grand mean for all environments, fi is the genetic effect, ei is the effect of different environments, and εi is the random error
Root to shoot ratio increase, an initial response to Zn deficiency, is one of the most sensitive indicators to characterize Zn efficiency (ZE). This response indicates a compensation mechanism that plants could allocate the photosynthetic products produced by the shoot to root growth (Rengel and Graham, 1995), which may lead to greater morphological changes in the roots (Genc et al, 2007)
Summary
Specialty section: This article was submitted toPlant Nutrition, a section of the journal Frontiers in Plant ScienceReceived: 10 July 2021 Accepted: 30 September 2021 Published: 15 November 2021. Specialty section: This article was submitted to. Plant Nutrition, a section of the journal Frontiers in Plant Science. Maize (Zea mays L.) is the third most important cereal crop globally, after wheat and rice, and is a foundational model for genetics and genomics (Jiao et al, 2017). It accounts for about 64% of coarse grain and 27.1% of the total cereal production, providing at least 30% of food calories to more than 4.5 billion people in 94 developing countries (Shiferaw et al, 2011; Wu and Guclu, 2013). Maize is an important crop to solve the cereal demand in China
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