MARCADORES MOLECULARES TIPO SNP’s CANDIDATOS LIGADOS À RESISTÊNCIA A NEMATOIDE DE CISTO DE SOJA RAÇA 14 EM CULTIVARES DE SOJA BRASILEIRAS

Abstract

The cyst nematode (NCS) is one of the most damaging pathogens in soybean producing areas. With their high genetic variability, the use of DNA markers became useful tools to break this barrier because it presents a high degree of identification of source of variation of genetic resistance. The objective of this work was to determine candidate SNPs molecular markers linked to resistance to NCS, race 14, in Brazilian soybean cultivars. The experiment was conducted in a greenhouse in a completely randomized design, each experimental unit was characterized by a group of 6 tubes with 6 replicates. The distribution of the 46 cultivars was randomly, also for the differentiating series, which were seeded in plastic trays with a capacity of 54 tubes of 180cm³, filled with soil and medium sand in the proportion of 1: 3, with 2 seeds per tube. 3000 eggs were inoculated, and after 30 days, the number of females per root was quantified. The reactions were determined by the female index (IF). Databases were used to associate genetic markers to NCS race 14 genes such as NCBI, Scopus, Science Direct and CAPES Periods, as well as the SoyBase platform to track SNPs. A total of 46 cultivars were genotyped considering a coefficient of ancestry coefficient (≥ 0.70) for each genetic group, but it is not, however, an organization coincident with a response of resistance and susceptibility to NCS. Among the 46 cultivars tested only TMG 4182, BRS MT Pintado were resistant (4%) in the phenotypic test while BRS GO Chapadões, BRS GO Ipameri, NK 7059, BMX Extra, BRS 263, SYN 1059, BMX Focus, CD 237, NK 7059 expressed moderate resistance (17%), all of which were postulated as candidates for the search for SNP-type markers linked to NCS resistance, race 14.. Of the 48 SNPs markers screened in the SoyBase based on the literature, only 6 markers, Gm16_33360539_T_C; Gm16_35700223_G_T; Gm17_32038975_T_G; Gm18_1620585_T_C; Gm18_3169557_A_C and Gm18_4680723_C_T, showed compatibility with the results obtained by mapping the 316 SNPs candidates for resistance to NCS, race 14. The collection of commercial soybean cultivars evaluated showed a significant genetic divergence and structured in two main groups with slight signs of substructure for ΔK = 5 and 7, highlighting the growing mixed ancestry among the cultivars. The correlation between the phenotypic and molecular results indicated that only the SNPs markers 60, 110 and 244 were related to the low nematode infestation, being these candidates for resistance to the soybean cyst nematode race 14. The SNP 110 marker showed a very high correlation (-0.40), in addition to having direct effect with the SNPs markers 60 and 244 with binding to the IF variable, becoming the main candidate marker.