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ARS Home » Southeast Area » Tifton, Georgia » Research » Publications at this Location » Publication #343739
Title: Maternal stress reduces the susceptibility of Meloidogyne arenaria progeny to Pasteuria penetrans

Author
item LIU, CHANG - University Of Georgia
item Timper, Patricia - Patty

Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: 8/14/2017
Publication Date: 12/31/2017
Citation: Liu, C., Timper, P. 2017. Maternal stress reduces the susceptibility of Meloidogyne arenaria progeny to Pasteuria penetrans. Journal of Nematology. 49:512.

Interpretive Summary:

Technical Abstract: Pasteuria penetrans is an obligate parasite of Meloidogyne spp. Endospores of P. penetrans attach to the cuticle of the second-stage juvenile (J2) and the bacterium completes its life cycle in the mature female nematode; infected females are filled with millions of endospores and produce few to no eggs. Research with Pasteuria ramosa and water fleas has shown that a poor maternal environment increases resistance to P. ramosa. Therefore, we hypothesized that female nematodes that were under stress would produce progeny that were more resistant to P. penetrans. In the greenhouse, we created two environments for Meloidogyne arenaria: stressed as a result of crowding and non-stressed. The stressed treatment was inoculated with 5000 J2 per pot and the foliage of the host plant (eggplant) was pruned to reduce root growth. The non-stressed treatment was inoculated with 1000 J2 and no pruning was done. Two months after inoculation, the soil was sampled for the presence of males (an indication of population stress) and eggs were extracted from females in the stressed and non-stressed treatments. The eggs were hatched to obtain J2, and the J2 were exposed to P. penetrans endospores to determine susceptibility to spore attachment. Juveniles with spores were also inoculated onto eggplant to determine the percentage of progeny which were infected by the bacterium. There were six replicates of each treatment and the experiment was conducted twice. Stressed treatments contained 3.4 males/100 cm3 of soil and non-stressed treatments contained no males. There was no difference in attachment of endospores to progeny from stressed and non-stressed environments, both treatments averaged 5.8 spores/J2. However, the percentage of females infected by P. penetrans was lower in progeny from stressed (8%) than from non-stressed (18%) mothers. These findings suggest that populations of Meloidogyne spp. that reach the carrying capacity of their host plant, as often happens at the end of the season, may generate progeny which are less susceptible to infection by P. penetrans than are populations not competing for nutrition.