TY - JOUR

T1 - Assessing the variation in traits for manganese deficiency tolerance among maize genotypes

AU - Long, Lizhi

AU - Kristensen, Rebekka Kjeldgaard

AU - Guo, Jingxuan

AU - Chen, Fanjun

AU - Pedas, Pai Rosager

AU - Zhang, Guoping

AU - Schjoerring, Jan Kofod

AU - Yuan, Lixing

PY - 2021

Y1 - 2021

N2 - Deficiency of manganese (Mn) is a serious problem reducing crop yields on calcareous and sandy soils throughout the world. In maize, limited knowledge is available on genotypic differences in tolerance to low-Mn supply and the physiological mechanisms underlying this tolerance. In the present study we have evaluated twelve maize genotypes (inbred lines) for their tolerance to Mn deficiency. The evaluation was based on measurements of how low-Mn supply affected shoot biomass, leaf Mn concentrations, maximum quantum efficiency of photosystem II (Fv/Fm), photosynthetic net CO2 assimilation, root length, Mn uptake and root-shoot Mn translocation. Tolerant genotypes were able to maintain optimum Fv/Fm values under a longer period of Mn deficiency with less reduction of foliar Mn concentration and photosynthetic rate, resulting in less reduction of shoot biomass, compared to sensitive genotypes. Efficient root uptake of Mn and root-to-shoot translocation of Mn also contributed to improved tolerance to Mn-deficiency. The metal transport genes YSL, NRAMP, ZIP, CAX and MTP, involved in root Mn uptake, root-to-shoot Mn translocation and vacuolar Mn homeostasis, were more highly expressed in the efficient genotype K22compared to sensitive genotype BY815. With respect to breeding of maize cultivars with improved Mn-efficiency, the time-course of changes in Fv/Fm values in response to Mn-deficiency provides a useful screening index for low-Mn tolerance.

AB - Deficiency of manganese (Mn) is a serious problem reducing crop yields on calcareous and sandy soils throughout the world. In maize, limited knowledge is available on genotypic differences in tolerance to low-Mn supply and the physiological mechanisms underlying this tolerance. In the present study we have evaluated twelve maize genotypes (inbred lines) for their tolerance to Mn deficiency. The evaluation was based on measurements of how low-Mn supply affected shoot biomass, leaf Mn concentrations, maximum quantum efficiency of photosystem II (Fv/Fm), photosynthetic net CO2 assimilation, root length, Mn uptake and root-shoot Mn translocation. Tolerant genotypes were able to maintain optimum Fv/Fm values under a longer period of Mn deficiency with less reduction of foliar Mn concentration and photosynthetic rate, resulting in less reduction of shoot biomass, compared to sensitive genotypes. Efficient root uptake of Mn and root-to-shoot translocation of Mn also contributed to improved tolerance to Mn-deficiency. The metal transport genes YSL, NRAMP, ZIP, CAX and MTP, involved in root Mn uptake, root-to-shoot Mn translocation and vacuolar Mn homeostasis, were more highly expressed in the efficient genotype K22compared to sensitive genotype BY815. With respect to breeding of maize cultivars with improved Mn-efficiency, the time-course of changes in Fv/Fm values in response to Mn-deficiency provides a useful screening index for low-Mn tolerance.

KW - Chlorophyll fluorescence

KW - Genetic variation

KW - Maize (zea maysL.)

KW - Manganese

KW - Metal transporters

KW - Photosynthesis

U2 - 10.1016/j.envexpbot.2020.104344

DO - 10.1016/j.envexpbot.2020.104344

M3 - Journal article

AN - SCOPUS:85097882136

VL - 183

JO - Environmental and Experimental Botany

JF - Environmental and Experimental Botany

SN - 0098-8472

M1 - 104344

ER -