Showing papers by "Isgouhi Kaloshian published in 2003"
TL;DR: The results suggest that aphid feeding involves both SA and JA/ethylene plant defense signaling pathways and that Mi-1-mediated resistance might involve a SA-dependent signaling pathway.
Abstract: The tomato Mi-1 gene confers resistance to three species of root-knot nematode and potato aphid. We studied changes in expression of jasmonic acid (JA)- and salicylic acid (SA)-dependent defense genes in response to potato and green peach aphids. We determined changes in three PR proteins, lipoxygenase and proteinase inhibitors I and II transcripts, locally and systemically in both compatible and incompatible interactions in tomato. Transcripts for PR-1 were detected earlier and accumulated to higher levels in the incompatible than in the compatible potato aphid/tomato interactions. The transcript profiles of the other genes were similar in compatible compared with incompatible interactions. Pin1 and Pin2 RNAs were detected early and transiently in both compatible and incompatible interactions. In tomato plants containing Mi-1, systemic expression of PR-1 and GluB was detected in both compatible and incompatible interactions at 48 h after infestations with either aphid. These results suggest that aphid feeding involves both SA and JA/ethylene plant defense signaling pathways and that Mi-1-mediated resistance might involve a SA-dependent signaling pathway. Potato aphid feeding generated reactive oxygen species in both compatible and incompatible interactions. However, a hypersensitive response was absent in the Mi-1-mediated resistance response to potato aphids. Reciprocal grafting experiments revealed that resistance is cell autonomous, and local expression of Mi-1 is required for Mi-1-mediated resistance against the potato aphid.
231 citations
TL;DR: Based on recent molecular evidence, several scenarios involving phytohormones in the induction of giant cells by root-knot nematodes are presented and parallels with aphid-plant interactions are emphasized.
139 citations
TL;DR: A novel heat-stable nematode resistance gene from the wild species Lycopersicon peruvianum accession LA2157 on to chromosome 6 is identified and designated as Mi-9, and a linkage map around this gene is constructed.
Abstract: The tomato gene Mi-1 confers resistance to three species of root-knot nematodes, Meloidogyne spp. However, the resistance mediated by Mi-1 is inactive at soil temperatures above 28 °C. Previously, we identified and mapped a novel heat-stable nematode resistance gene from the wild species Lycopersicon peruvianum accession LA2157 on to chromosome 6. Here we report further characterization of this heat-stable resistance against three Mi-1-avirulent biotypes of Meloidogyne javanica, Meloidogyne arenaria and Meloidogyne incognita. Screening segregating F2 and F3 progenies, derived from an intraspecific cross between susceptible LA392 and resistant LA2157, for nematode resistance at 25 °C and 32 °C, revealed a simple dominant monogenic inheritance with all the biotypes tested. We designate this gene as Mi-9. As a first step towards cloning of Mi-9, we constructed a linkage map around this gene. A total of 216 F2 progeny from the cross between LA392 and LA2157 were screened with M. javanica at 32 °C and with CT119 and Aps-1, markers that flank the genetic interval that contains the Mi-1 gene. DNA marker analysis indicated that these markers also flank Mi-9. Further mapping of recombinants with both RFLP and PCR-based markers localized Mi-9 to the short arm of chromosome 6 and within the same genetic interval that spans the Mi-1 region.
104 citations
01 Jan 2003
1 citations