QTL analysis reveals quantitative resistant loci for <i>Phytophthora infestans</i> and <i>Tecia solanivora</i> in tetraploid potato (<i>Solanum tuberosum</i> L.)

<div><p>Late blight and Guatemalan potato tuber moth caused by <i>Phytophthora infestans</i> and <i>Tecia solanivora</i>, respectively, are major phytosanitary problems on potato crops in Colombia and Ecuador. Hence, the development of resistant cultivars is an alternative for their control. However, breeding initiatives for durable resistance using molecular tools are limited due to the genome complexity and high heterozygosity in autotetraploid potatoes. To contribute to a better understanding of the genetic basis underlying the resistance to <i>P</i>. <i>infestans</i> and <i>T</i>. <i>solanivora</i> in potato, the aim of this study was to identify QTLs for resistance to <i>P</i>. <i>infestans</i> and <i>T</i>. <i>solanivora</i> using a F1 tetraploid potato segregant population for both traits. Ninety-four individuals comprised this population. Parent genotypes and their progeny were genotyped using SOLCAP 12K potato array. Forty-five percent of the markers were polymorphic. A genetic linkage map was built with a length of 968.4 cM and 1,287 SNPs showing good distribution across the genome. Severity and incidence were evaluated in two crop cycles for two years. QTL analysis revealed six QTLs linked to <i>P</i>. <i>infestans</i>, four of these related to previous QTLs reported, and two novel QTLs (qrAUDPC-3 and qrAUDPC-8). Fifteen QTLs were linked to <i>T</i>. <i>solanivora</i>, being qIPC-6 and qOPA-6.1, and qIPC-10 and qIPC-10.1 stable in two different trials. This study is one of the first to identify QTLs for <i>T</i>. <i>solanivora</i>. As the population employed is a breeding population, results will contribute significantly to breeding programs to select resistant plant material, especially in countries where <i>P</i>. <i>infestans</i> and <i>T</i>. <i>solanivora</i> limit potato production.</p></div

Incidence of <i>Tecia solanivora</i>.

<p>Histogram of incidence of number of individuals of <i>Tecia solanivora</i> under field conditions in two consecutive years (2015 and 2016). The black triangle indicates the phenotypic value of Roja Nariño and the grey one indicates the value of BGVCOL 15062384.</p

QTLs for resistance to <i>Phytophthora infestans</i> found in the RN × 2384 population.

<p>QTLs for resistance to <i>Phytophthora infestans</i> found in the RN × 2384 population.</p

Summary of the genetic map of the potato population RN × 2384.

<p>Summary of the genetic map of the potato population RN × 2384.</p

Resistance evaluation to <i>Phytophthora infestans</i> and <i>Tecia solanivora</i> in the potato segregating tetraploid population RN × 2384.

<p>Resistance evaluation to <i>Phytophthora infestans</i> and <i>Tecia solanivora</i> in the potato segregating tetraploid population RN × 2384.</p

QTLs identified for resistance to <i>Tecia solanivora</i> in the RN x 2384 population.

<p>QTLs identified for resistance to <i>Tecia solanivora</i> in the RN x 2384 population.</p

<i>Tecia solanivora</i> severity based on number of output holes (OPA).

<p>The x-axis shows the output holes number in each tuber, while on the y-axis shows number of individuals. The dotted line indicates the average trend. The black triangle indicates the phenotypic value of Roja Nariño and the grey one de value of BGVCOL 15062384.</p

Population screening of <i>Tecia solanivora</i>.

<p>Fluctuation of adult male populations of <i>Tecia solanivora</i> during the field trials for years 2015 and 2016. Evaluations were conducted weekly using a sexual pheromone trap during two crop cycles in consecutive years 2015 (continuous line) and 2016 (dotted line).</p

Linkage map and QTLs for <i>Tecia solanivora</i> and <i>Phytophthora infestans</i>.

<p>The position of the marker in centimorgans is shown in the y-axis. Black bars show <i>T</i>. <i>solanivora</i> QTL locations, meanwhile white bars show <i>P</i>. <i>infestans</i> QTL locations.</p

Hydroxycinnamic acid functional ingredients and their biosynthetic genes in tubers of <i>Solanum tuberosum</i> Group Phureja

<p>Potato is an ideal candidate for the delivery of functional ingredients due to its high worldwide consumption. The metabolites in cooked tubers of eight diploid potato genotypes from Colombia were explored. Potato tubers were harvested, cooked，lyophilized, and then stored at −80°C. Metabolites were extracted from flesh samples and analyzed using liquid chromatography and high-resolution mass spectrometry. A total of 294 metabolites were putatively identified, of which 87 metabolites were associated with health-benefiting roles for humans, such as anticancer and anti-inflammatory properties. Two metabolites, chlorogenic acid and N-Feruloyltyramine were detected in high abundance and were mapped on to the potato metabolic pathways to predict the related biosynthetic enzymes: hydroxycinnamoyl-CoA quinate transferase (HQT) and tyramine hydroxycinnamoyl transferase (THT), respectively. The coding genes of these enzymes identified nonsynonymous single-nucleotide polymorphisms (nsSNPs) in AC09, AC64, and Russet Burbank, with the highest enzyme stability found in AC09. This is consistent with the highest presence of hydroxycinnamic acids in the AC09 genotype. The metabolites detected at high fold change, their functional ingredient properties, and their enhancement through breeding to improve health of the indigenous communities’ of Colombia are discussed.</p