Host genotype and the formation and function of VA mycorrhizae

• Published in: Plant and soil Vol. 159; no. 1; pp. 179 - 185
• Main Authors: Graham, J.H. (Florida Univ., Lake Alfred, FL (USA). Citrus Research and Education Centre), Eissenstat, D.M
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Dordrecht Kluwer Academic Publishers 01-02-1994; Springer
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Fungi; Genetic variation; Genotypes; MICORRIZAS ARBUSCULARES VESICULARES; Microbial colonization; MYCORHIZE A VESICULE ET ARBUSCULE; Mycorrhizae; Mycorrhizal fungi; Orchard soils; Parasitism and symbiosis; Plant physiology and development; Plant roots; Plants; SIMBIOSIS; Soil fungi; SYMBIOSE; SYMBIOSIS; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); VESICULAR ARBUSCULAR MYCORRHIZAE; Symbiosis; Symbiotic relation; Nutrition; Root; Citrus fruit; Rutaceae; Genotype; Review; Metabolism; Carbon; Citrus; Fungi; Leguminosae; Dicotyledones; Pisum sativum; Angiospermae; Mycorrhiza; Dependence; Spermatophyta; Fruit tree; Compatibility; Performance; Colonization; Thallophyta
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/bf00000107

VA mycorrhizae, the most ancient type of mycorrhizal symbiosis, are present in the most phytogenetically advanced groups. Few plants have evolved mechanisms to completely prevent infection by VAM fungi. Yet, plant species that are less dependent on VA mycorrhizae for nutrient acquisition (e. g., grasses) generally have less root colonization in the field than more dependent species (e. g., Citrus). Among closely related Citrus genotypes, there is a greater tendency for less dependent species to limit the rate but not the extent of colonization, even in high-P soils. We hypothesize that colonization represents a significant carbon cost that may be regulated by the host genotype. Carbon expenditure on the fungus at high P may result in mycorrhizal-induced growth depression. The potential value of breeding plants for greater susceptibility to colonization will depend on the cost/benefit of VA mycorrhizae for the specific crop, soil and environmental conditions. Although the genetics and physiology of host control over VAM colonization are barely known, recently discovered mycorrhizal colonization mutants (myc⁻) of pea offer great promise for the study of host-fungus compatibility.