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United States Department of Agriculture

Agricultural Research Service

Title: Usefulness of WRKY gene-derived markers for assessing genetic diversity of Florida coconut cultivars

Authors
item Mauro Herrera, Margarita
item Meerow, Alan
item Borrone, James
item Kuhn, David
item Schnell Ii, Raymond

Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2007
Publication Date: November 13, 2007
Citation: Mauro Herrera, M., Meerow, A.W., Borrone, J.W., Kuhn, D.N., Schnell Ii, R.J. 2007. Usefulness of WRKY gene-derived markers for assessing genetic diversity of Florida coconut cultivars. Scientia Horticultureae. 115:19-26.

Interpretive Summary: We used 13 genetic markers derived from WRKY genes – a group of functional genes implicated in disease resistance – to analyzed patterns of genetic variation and diversity within and among 7 coconut varieties, using the same individual coconut samples previously analyzed with 15 microsatellite repeat markers. Our results show good correspondence between the the two types of genetic markers. Individuals of cultivars 'Red Malayan Dwarf', ‘Fiji Dwarf’ and 'Red Spicata' were clearly clustered, as in the previous analysis. However, individuals of 'Green Malayan Dwarf' and 'Yellow Malayan Dwarf' were resolved with other cultivars, perhaps due to selective forces operating on these functional genes. Most samples of the 'Atlantic Tall' and 'Panama Tall' cultivars clustered together as in the previous microsatellite study. We discuss the utility of WRKY-derived markers for assessing the genetic diversity of coconut, and their possible value in the study of other species.

Technical Abstract: Analysis of the genetic diversity and population structure within Florida coconut (Cocos nucifera L.) germplasm representing eight cultivars was previously described using 15 microsatellite (simple sequence repeat, SSR) markers. Here we report on the analysis of the same genotypes using 13 markers derived from WRKY sequences containing single nucleotide polymorphisms (SNP) and one microsatellite. WRKY transcription factors are unique to plants and are involved in numerous vital processes including disease resistance. Our objective was to determine the value of this type of gene to assess the genetic diversity of this species. Our results show good correspondence between the previous results using microsatellite markers and the WRKY-derived markers, despite the lower number of alleles identified with the WRKY-derived markers. Individuals of cultivars 'Red Malayan Dwarf', 'Fiji Dwarf' and 'Red Spicata' were clearly clustered, as in the previous analysis. However, individuals of 'Green Malayan Dwarf' and 'Yellow Malayan Dwarf' were resolved with other cultivars, perhaps due to selective forces operating on these functional genes. Most samples of the 'Atlantic Tall' and 'Panama Tall' cultivars clustered together as in the previous microsatellite study. We discuss the utility of WRKY-derived markers for assessing the genetic diversity of coconut, and their possible value in the study of other species.

Last Modified: 7/22/2014
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