Mycorrhizal fungi improve yield, biomass and nitrogen fixation by rhizobia but increase population densities of the root-lesion nematode Pratylenchus thornei in mung bean

Qld-APPS Seminars

Mung bean is a short-season, high-value legume crop in eastern Australia that is susceptible to the plant-parasitic root-lesion nematode Pratylenchus thornei. It also forms associations with the beneficial soil-borne arbuscular mycorrhizal fungi (AMF) which increases plant uptake of phosphorus (P) and zinc (Zn) in exchange for photosynthates. Interactions with AMF and biotic stressors in previous studies suggested that AMF may induce a biocontrol effect to reduce symptom severity and Pratylenchus population density in crops. Presented for the Queensland Chapter of the Australasian Plant Pathology Society (APPS).

Adam Sparks https://adamhsparks.com
07-31-2021

About

Presenter: Ms Elaine Gough
Institution: University of Southern Queensland, Centre for Crop Health
Host: Queensland Chapter Australasian Plant Pathology Society, @qldapps
Links: Video

Biography

I am currently completing my PhD at the Centre for Crop Health, University of Southern Queensland where I am investigating interactions between arbuscular mycorrhizal fungi, rhizobia and root-lesion nematodes in mung bean. I have a keen interest in sustainable agriculture and soil micro-biology and am passionate about highlighting the amazing benefits and economic gains to be made when we understand more about the ground beneath our feet.

Abstract

Mung bean (Vigna radiata) is a short-season high-value legume integrated into grain cropping sequences in the sub-tropical grain region of eastern Australia. It benefits crop rotations through its ability to fix nitrogen (N) from inoculation with Bradyrhizobium. It also forms associations with the beneficial soil-borne arbuscular mycorrhizal fungi (AMF) which increases plant uptake of phosphorus (P) and zinc (Zn) in exchange for photosynthates.

Mung bean also hosts the plant-parasitic root-lesion nematode Pratylenchus thornei. Multiplication of P. thornei) in roots can reduce yield of mung bean and subsequent intolerant crops in the sequence. Interactions with AMF and biotic stressors in previous studies suggested that AMF may induce a biocontrol effect to reduce symptom severity and Pratylenchus population density in crops.

Our research demonstrated that co-inoculation with AMF and Bradyrhizobium synergistically increased (P<0.001) seed yield, shoot biomass, nodulation, biological N fixation and plant nutrition of mung bean cv Jade-AU in glasshouse experiments in a pasteurised vertisol. However, AMF also significantly increased (P<0.05) the population density of P. thornei in mung bean roots, which was not correlated with increased root biomass or improved plant nutrition. Pratylenchus thornei also reduced P and Zn concentration, while increasing N concentration in mycorrhizal shoots.

Integrated management to prevent increases in P. thornei in farming systems is imperative so that we can harness the benefits of AMF to improve mung bean yield and nutrition. Rotations with crops that reduce P. thornei populations while increasing AMF inoculum levels in the soils is warranted.

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