Abstract
ABSTRACTRoot-knot nematodes (RKNs) are among the most devastating pests in agriculture. Solanum torvum Sw. (turkey berry) has been used as a rootstock for eggplant (aubergine) cultivation because of its resistance to RKNs, including Meloidogyne incognita and M. arenaria. We previously found that a pathotype of M. arenaria, A2-J, is able to infect and propagate in S. torvum. In vitro infection assays showed that S. torvum induces the accumulation of brown pigments during avirulent pathotype A2-O infection, but not during virulent A2-J infection. This experimental system is advantageous because resistant and susceptible responses can be distinguished within a few days, and because a single plant genome can yield information about both resistant and susceptible responses. Comparative RNA-sequencing analysis of S. torvum inoculated with A2-J and A2-O at early stages of infection was used to parse the specific resistance and susceptible responses. Infection with A2-J did not induce statistically significant changes in gene expression within one day post-inoculation (DPI), but afterward, A2-J specifically induced the expression of chalcone synthase, spermidine synthase, and genes related to cell wall modification and transmembrane transport. Infection with A2-O rapidly induced the expression of genes encoding class III peroxidases, sesquiterpene synthases, and fatty acid desaturases at 1 DPI, followed by genes involved in defense, hormone signaling, and the biosynthesis of lignin at 3 DPI. Both isolates induced the expression of suberin biosynthetic genes, which may be triggered by wounding during nematode infection. Histochemical analysis revealed that A2-O, but not A2-J, induced lignin accumulation at the root tip, suggesting that physical reinforcement of cell walls with lignin is an important defense response against nematodes. The S. torvum-RKN system can provide a molecular basis for understanding plant-nematode interactions.
Publisher
Cold Spring Harbor Laboratory
Reference155 articles.
1. Abad, P. , Castagnone-Sereno, P. , Rosso, M.N. , Engler, J.d.A. , and Favery, B. (2009). “Invasion, Feeding and Development,” in Root-knot nematodes, eds. R.N. Perry , M. Moens & J.L. Starr . (Cambridge: CABI International Press), 163–181.
2. The endodermis—development and differentiation of the plant’s inner skin
3. Changes in wheat root enzymes correlated with resistance to cereal cyst nematodes
4. SlWRKY70 is required for Mi-1-mediated resistance to aphids and nematodes in tomato
5. Solanum torvum responses to the root-knot nematode Meloidogyne incognita