Abstract Detail



Pelton Award Lecture - Neelima Sinha

Singha, Neelima [1].

Interactions between the parasitic plant Cuscuta and its tomato host.

Parasitic angiosperms directly attach to host plants using specialized organs known as haustoria, which function as physiological bridges to extract nutrients and water from their hosts. Cuscuta species (dodders) are common and agriculturally destructive flowering stem parasitic plants. Many Cuscuta species are listed in the Federal or State Noxious Weed lists, including Cuscuta pentagona (C. pentagona). Reports have shown a 50–72% reduction in tomato yield due to Cuscuta. Because of the intimate physiological connection between host plants and parasites, most traditional herbicides and control methods have not been effective or are too costly. We used transcriptomics to identify genes upregulated in Cuscuta upon attachment to host. Expression of key upregulated genes was reduced using host-induced-gene-silencing and haustorium formation monitored. Reduction in expression of some of the identified genes attenuated parasitism. While most tomato cultivars can be parasitized by C. pentagona, we obtained some Heinz hybrid cultivars, which exhibited resistance to dodders. Local lignification in the stem cortex upon dodder attachment led to resistance to haustorium penetration in the resistant cultivars. Key resistance genes included an AP2-like transcription factor, a MYB transcription factor and an NBS-LRR (a gene encoding a nucleotide-binding site leucine-rich repeat protein). The function of these genes was deciphered using virus based gene expression. The results of this study may help develop a parasite-resistant system in crops to reduce economic losses in agriculture.


1 - University of California - Davis, CA

Keywords:
dodder
haustoria
parasitism
lignification
host-induced-gene-silencing.

Presentation Type: Special Presentation
Number:
Abstract ID:1030
Candidate for Awards:None


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