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United States Department of Agriculture

Agricultural Research Service

Research Project: HOST PLANT RESISTANCE AND OTHER MANAGEMENT STRATEGIES FOR NEMATODES IN COTTON AND PEANUT

Location: Crop Protection and Management Research

Title: A technique to study Meloidogyne arenaria resistance in Agrobacterium rhizogenes-transformed peanut

Authors
item Chu, Y -
item Wu, C -
item Timper, Patricia
item Holbrook, C
item Ozias-Akins, P -

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 18, 2014
Publication Date: N/A

Interpretive Summary: A reliable peanut root transformation system would be useful to study the functions of genes involved in root biology and disease resistance. The objective of this study was to establish an effective protocol to produce composite plants using Agrobacterium rhizogenes, a bacterium that infects peanut roots, to deliver genes into plants (transform) to study how the genes function. More than 70% of transformed peanut seedlings produced an average of 1.6-3.2 transgenic roots. Peanut seeds had the highest germination rate after treatment in a chlorine gas chamber for 8 h compared to other sterilization procedures. High transformation efficiency was achieved when the wound site for Agrobacterium inoculation was covered with vermiculite instead of enclosing the whole plant in a high humidity chamber. An average of 2.5 galls from nematode infection was formed per transgenic root from a susceptible genotype TifGP-2. These data indicate that Agrobacterium-transformed roots can be used to assess the host response to nematode challenge. Transformation of the RLP-2, a candidate resistance gene for root-knot nematode, integrated as a gene-silencing construct did not alter the resistance response of Tifguard. It is likely that RLP-2 is not the gene conditioning nematode resistance in peanut.

Technical Abstract: A reliable peanut root transformation system would be useful to study the functions of genes involved in root biology and disease resistance. The objective of this study was to establish an effective protocol to produce composite plants mediated by Agrobacterium rhizogenes transformation. More than 70% of transformed peanut seedlings produced an average of 1.6-3.2 transgenic roots. Peanut seeds had the highest germination rate after treatment in a chlorine gas chamber for 8 h compared to other sterilization procedures. High transformation efficiency was achieved when the wound site for A. rhizogenes inoculation was covered with vermiculite instead of enclosing the whole plant in a high humidity chamber. An average of 2.5 galls from nematode infection was formed per transgenic root from a susceptible genotype TifGP-2. These data indicate that A. rhizogenes transformed roots can be used to phenotype the host response to nematode challenge. Transformation of the RLP-2, a candidate resistance gene for root-knot nematode, integrated in a silencing construct did not alter the resistance response of Tifguard. It is likely that RLP-2 is not the gene conditioning nematode resistance in peanut; however, further study is needed to definitively show the reduction of endogenous RLP-2 expression in transgenic roots.

Last Modified: 7/24/2014
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