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Date of Graduation

5-2026

Description

Reniform nematode (Rotylenchulus reniformis, RN) is a major plant-pest affecting key crops in Arkansas such as cotton and soybean, causing economic losses exceeding $757 million in the U.S. over the past decade. While some genetic resistance exists in cotton, soybean remains highly susceptible, exacerbating RN populations in crop rotations. To address this gap, this research investigates the mechanisms of nematode infection focusing on effectors, the specialized proteins secreted by the parasite to manipulate host cell biology and suppress plant immunity. This study characterizes Rr6640, a putative effector gene identified as an ortholog to a virulence factor in the Beet Cyst Nematode (Heterodera schachtii). Given the similar sedentary feeding strategies of cyst and reniform nematodes, we hypothesize that Rr6640 plays a conserved, critical role in successful parasitism. To test this hypothesis, the current work employed a multi-step molecular cloning and functional validation process. First, the Rr6640 gene was isolated and cloned into the pBIN::GFP overexpression vector. This construct was transformed into Agrobacterium strains to facilitate two parallel experiments. We are currently utilizing Agrobacterium rhizogenes K599 to generate transgenic soybean hairy roots, to assess if the gene enhances nematode infection rates. Additionally, we are conducting Agrobacterium tumefaciens GV2260-mediated transient assays in Nicotiana benthamiana to determine if Rr6640 can suppress programmed cell death, which will indicate if the gene has a role in suppressing plant immune responses. Preliminary results confirm the successful isolation, cloning, and bacterial transformation of the Rr6640 gene, validated through gel electrophoresis and Sanger sequencing. Current work is focused on confirming stable protein expression in plant tissues. By elucidating the function of Rr6640, this research contributes to a deeper understanding of nematode-plant interactions and identifies potential genetic targets for engineering resistant soybean crops, ultimately reducing nematode-related crop losses in Arkansas.

Publication Date

2026

Document Type

Book

Degree Name

Bachelor of Science in Agriculture

Degree Level

Undergraduate

Department

Crop, Soil & Environmental Sciences

Advisor/Mentor

Kud, Joanna

Disciplines

Agriculture

Keywords

Natural Science

Functional Characterization of the Reniform Nematode Effector Protein Rr6640 in Soybean Parasitism

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Agriculture Commons

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