Arbuscular mycorrhizal symbioses alleviating salt stress in maize is associated with a decline in root-to-leaf gradient of Na + /K + ratio
Inoculation of arbuscular mycorrhizal (AM) fungi has the potential to alleviate salt stress in host plants through the mitigation of ionic imbalance. However, inoculation effects vary, and the underlying mechanisms remain unclear. Two maize genotypes (JD52, salt-tolerant with large root system, and...
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Published in | BMC plant biology Vol. 21; no. 1; p. 457 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
BioMed Central Ltd
07.10.2021
BioMed Central BMC |
Subjects | |
Online Access | Get full text |
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Summary: | Inoculation of arbuscular mycorrhizal (AM) fungi has the potential to alleviate salt stress in host plants through the mitigation of ionic imbalance. However, inoculation effects vary, and the underlying mechanisms remain unclear. Two maize genotypes (JD52, salt-tolerant with large root system, and FSY1, salt-sensitive with small root system) inoculated with or without AM fungus Funneliformis mosseae were grown in pots containing soil amended with 0 or 100 mM NaCl (incrementally added 32 days after sowing, DAS) in a greenhouse. Plants were assessed 59 DAS for plant growth, tissue Na
and K
contents, the expression of plant transporter genes responsible for Na
and/or K
uptake, translocation or compartmentation, and chloroplast ultrastructure alterations.
Under 100 mM NaCl, AM plants of both genotypes grew better with denser root systems than non-AM plants. Relative to non-AM plants, the accumulation of Na
and K
was decreased in AM plant shoots but increased in AM roots with a decrease in the shoot: root Na
ratio particularly in FSY1, accompanied by differential regulation of ion transporter genes (i.e., ZmSOS1, ZmHKT1, and ZmNHX). This induced a relatively higher Na
efflux (recirculating) rate than K
in AM shoots while the converse outcoming (higher Na
influx rate than K
) in AM roots. The higher K
: Na
ratio in AM shoots contributed to the maintenance of structural and functional integrity of chloroplasts in mesophyll cells.
AM symbiosis improved maize salt tolerance by accelerating Na
shoot-to-root translocation rate and mediating Na
/K
distribution between shoots and roots. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1471-2229 1471-2229 |
DOI: | 10.1186/s12870-021-03237-6 |