|Wang, Cogli - UNIVERSITY OF CALIFORNIA|
|Hutmacher, Robert - UNIVERSITY OF CALIFORNIA|
|Stelly, David - TEXAS A&M UNIVERSITY|
|Roberts, Philip - UNIVERSITY OF CALIFORNIA|
Submitted to: Genetica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2016
Publication Date: 4/12/2016
Citation: Ulloa, M., Wang, C., Saha, S., Hutmacher, R.B., Stelly, D.M., Jenkins, J.N., Roberts, P. 2016. Analysis of root-knot nematode and fusarium wilt disease resistance in cotton (Gossypium spp.) using chromosome substitution lines from two alien species. Genetica. 144(2):167-179.
Interpretive Summary: Diseases caused by nematodes such as root-knot nematode (RKN) and caused by fungi such as Fusarium (FOV races 1 and 4) represent expanding threats to cotton production. Resistant cultivars are highly effective in preventing crop loss from RKN and FOV infection, economically important diseases in cotton. To identify a new resource of cotton types resistant to these two pests and favorable genes associated with nematode and fungal disease resistance traits, a series of cotton chromosome substitution (CS) lines were used in this study. RKN and FOV greenhouse and infested field evaluations identified CS lines with improved resistance. CS lines carrying small alien chromosome segments with favorable gene-alleles could be used for effective introgression of stress and disease resistance or many other desirable traits by targeting gene interactions and reducing barrier effects. Molecular marker analyses validated regions on cotton chromosomes 11, 16, and 17 harboring RKN, FOV race 1 and FOV race 4 resistance genes, respectively. Also, analyses from this study demonstrated the value of these cotton CS lines as both a germplasm resource for breeding programs and as a powerful genetic analysis tool for determining gene effects for disease resistance.
Technical Abstract: To Identify a new germplasm resource, and to validate chromosomal regions and favorable alleles associated with nematode and fungal disease resistance traits, a series of interspecific cotton (Gossypium spp.) chromosome substitution (CS) lines were used in this study. The CS lines were developed in the TM-1 background with chromosome or chromosome segment substitutions from G. barbadense L. Pima 3-79 or G. tomentosum. The root-knot nematode [Meloidogyne incognita (RKN)] and Fusarium wilt [Fusarium oxysporum f. sp. vasinfectum (FOV)] race 1 (FOV1) and race 4 (FOV4) resistance alleles and quantitative trait loci (QTL) were previously placed on cotton chromosomes using SSR markers in recombinant inbred line populations developed between Upland TM-1 (G. hirsutum L.) x Pima 3-79, and Acala NemX (G. hirsutum) x Pima-S7 (G. barbadense). Phenotypic responses of increased resistance or susceptibility in greenhouse inoculation and infested field assays confirmed the resistance QTLs. Lines CS-B22Lo and CS-B04 with alleles from Pima 3-79, showed high resistance to nematode root-galling, confirming QTLs Mi-GIb-C04 and Mi-Glb-C22. Line CS-B16 had less FOV1 vascular root staining (VRS) and higher field percent survival (PS) than the TM-1 parent, confirming FOV1 resistance QTL FOV1-C16 in 3-79. Lines CS-NTN17-11 and CS-B17 had high FOV4 VRS symptoms and low PS due to susceptible alleles introgressed from Pima 3-79, confirming the localization on chromosome 17 of a previously identified QTL with FOV4 resistance alleles from Acala NemX, Upland TM1, or Pima-S6. Analyses validated regions on chromosomes 11, 16, and 17 harboring RKN, FOV1 and FOV4 resistance genes, respectively and demonstrated the value of CS lines as both a germplasm resource for breeding programs and as a powerful genetic analysis tool for determining QTL effects for disease resistance. CS lines carrying small alien chromosome segments with favorable QTL alleles could be used for effective introgression of biotic stress resistance or many other desirable traits by targeting gene interactions and reducing linkage drag effects.