Inter-simple sequence repeat (ISSR) analysis of somaclonal variation in Sechium edule var. virens levis resistant to Phytophthora capsici

Abstract

Veracruz is the main producer of Sechium edule in Mexico, which is severely affected by Phytophthora capsici, a phytopathogen that affects roots, stems, leaves, and fruits, causing plant death. The molecular variation of S. edule vitroplants resistant to P. capsici was evaluated using inter-simple sequence repeat (ISSR) markers. Genomic DNA was extracted from S. edule mother plants and ten vitroplants showing resistance to P. capsici. Twenty primers were used to select those showing clarity, reproducibility and high number of amplified bands. Three primers were selected to analyze genetic variability. The profiles obtained from polymerase chain reactions (PCR) were recorded in a binary matrix, with 1 representing the presence of a band and 0 absence. The total number of amplified bands, the number of polymorphic bands, the percentage of polymorphic bands and the size of each band were recorded. The analysis showed variation in S. edule plants resistant to P. capsici compared the mother plants. Primers ISSRCR-8, UBC 808, and UBC-834 produced 13, 21, and 18 polymorphic bands with sizes of 250–2,500 bp, and 81.25, 100, and 100 % polymorphism, respectively, confirming the molecular variation in the somaclonal variants.