| The impact of vigor in the response of the small black soybean PI88788 and development of root-knot nematode, to infection with Meloidogyne incognita were examined. Five plant hormones of soybean root knots were determined using enzyme-linked immunoassay (ELISA). The relative gene expression of hormones between nematode and host plant were detected by Real Time PCR. Results were summarized as follows:1. The effect on the growth of soybean after inoculation:The results show that the height, root length and fresh weight on the ground is no obvious difference 5 DAI (days after inoculation). However, the height, root length and fresh weight on the ground is significantly inferior to control 7 DAI. The underground fresh weight and the root cap ratio were always higher than control within 28 DAI. 2. The study on the diversity of nematode infection amount and development:Only a small number of J2 were observed in lateral root at 3 DAI. These nematodes matured and completed its life cycle, with the growing of the small black soybean. M.incognita J2 counts reached the maximum at 7 DAI, while the J3 and J4 counts at 14 DAI,21 DAI respectively.3. Contents of plant hormones between root-knot nematode and soybean interaction:Five plant endogenesis hormones of soybean root knots were detected by enzyme-linked immunosorbent assay(ELISA). Data that convincingly show the contents variation of IAA, ABA, JA-Me, GA and ZR in the gall formation soybean roots. Among the hormones, JA-Me and ZR contents continuously higher than control within 28 DAI. IAA contents were significantly higher than those in control, whereas ABA contents were significantly lower than the control at early stage after inoculation. In contrast, IAA contents were always lower than the control within 5 DAI, but ABA contents were only significantly higher than those in control at the 14 DAI. GA contents were only higher than those in control at 21 DAI. ABA and GA contents were not significant different from those in control at other times. IAA/ABA and JA-Me/ABA ratio changed significantly, decreasing at the beginning and then rising as the curve trend. By contrast, there were no obvious change in the ratio of ZR/ABA and GA/ABA.4. The relative genes of plant hormones expression after inoculation:The relative genes of plant hormones were detected by quantitative RT-PCR, and the samples were took from soybean root knots tissue. The auxin-related genes, IAA-amino acid hydrolase ILR1-like 6-like and Indole-3-acetic acid-amido synthetase GH3.6-like, expressed significantly higher than the control at the 7th DAI. It inosculates well with the ELISA analytical results that IAA contents were significantly higher than those in control, at the initial stage after inoculation. The abscisic acid-related genes,9-cis-epoxycarotenoid dioxygenase NCED1a, 9-cis-epoxycarotenoid dioxygenase NCED1b and probable 9-cis-epoxycarotenoid dioxygenase NCED5, expressed obviously higher than those in control at the 14th DAI. It was same as the ELISA analytical results that ABA contents were significantly higher than those in control at the 14th DAI. The Jasmine acid-related genes, indole-3-aceticacid-amido synthetase GH3.5-like, expressed significantly higher than the control only at the 5th and 21th DAI, sometimes its lower than the those in control. In contrast, it was different from the ELISA analytical results that JA contents were always higher than the control within 28 DAI. The cytokinin-related genes, isopentenyl transferase, expressed obviously higher than those in control only at the 21th DAI. In contrast, it was different from the ELISA analysis results that ZR contents were always higher than the control after inoculation.This result reveals that the plant hormones contents would have various changes in soybean root knots, but the main trend is rise. Meanwhile, the hormones genes expression were elevated after inoculation, so the plant hormones could play a different role in giant cell formation of root knot nematode. |
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