Using host resistance to control cotton parasitic reniform nematode

Authors: Feng, Chunda; Stetina, Salliana

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/17/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Cotton is the primary source of natural fiber for the textile industry worldwide. The US is a leading cotton producer and the largest exporter in the international cotton market, representing about seven billion dollars total value annually. Reniform nematode (RN) is an increasing threat to the US cotton production, which causes about 1% yield loss to the total production (equivalent to hundreds of millions of dollars). In some southeast states, such as Alabama, Louisiana, Mississippi, and Tennessee, reniform nematode is becoming the most important disease for cotton production; the yield loss caused by this parasite is about 5% in these states and could be up to 50% in some heavily infested fields. Several approaches are applied to manage this important disease. Nematicides could provide protection to cotton seedlings for a short period, but the nematode populations increase dramatically during the cotton growing season. Rotation with non-host crops may reduce the populations of RN but is often not a choice due to some technical and economic constraints. Growing resistant (R) cultivars would be the most effective and sustainable way to manage this parasite. However, resistance to RN was not found in the widely grown tetraploid upland cotton (Gossypium hirsutum), but found in a few genotypes of tetraploid Sea Island cotton (G. barbadense) and some diploid Gossypium species. Therefore, the objectives of our research included identification of genetic resource of resistance to RN in diploid species and introgression of resistance from diploid to tetraploid upland cotton. Genetic and genomic approaches have been employed to characterize the RN resistance in this diploid Gossypium species. Using a genome-wide association study, we were able to identify some single nucleotide polymorphisms (SNPs) associated with resistance in G. herbaceum. Transcriptome analysis revealed differentially expressed genes (DEGs) in response to the RN. Some of these DEGs may play important roles in RN defense mechanism. Quantitative trait loci (QTLs) have been detected from two G. arboreum accessions, and candidate R genes were identified. Crossing tetraploid and diploid cotton usually results in embryo abortion due to post-zygotic barriers, and derived triploid seed would be sterile, making it impossible to directly introduce useful genes from diploid Gossypium species to tetraploid cultigens. The chromosome numbers of several G. arboreum R genotypes might be doubled using colchicine treatment, which was evidenced by the production of seed when pollinated with tetraploid upland cotton. Triploid plants of (G. hirsutum x G. arboreum) and (G. histutum x G. raimondii) were treated with colchicine, the treated plants produced seed and crossed with diploid species. The ploidy levels of the colchicine treated plants need to be determined. Overall, our efforts in characterization of the genetic basis of resistance in diploid Gossypium species and the development of intermediate breeding lines (potential artificial tetraploid G. arboreum and interspecific hexaploid) will be useful for developing resistant upland cotton cultivars by introgression of resistance from diploid species, and eventually using host resistance to control cotton parasitic RN.