Genetic Loci Conferring Reducing Sugar Accumulation and Conversion of Cold-Stored Potato Tubers Revealed by QTL Analysis in a Diploid Population

Abstract

Cold-induced sweetening (CIS) caused by reducing sugar (RS) accumulation during storage in low temperature in potato tubers is a critical factor influencing the quality of fried potato products. The reconditioning (REC) by arising storage temperature is a common measure to lower down RS. However, both CIS and REC are genotype-dependent and the genetic basis remains uncertain. In the present study, with a diploid potato population with broad genetic background, four reproducible QTL of CIS and two of REC were resolved on chromosomes 5, 6, and 7 of the CIS-sensitive parent and chromosomes 5 and 11 of the CIS-resistant parent, respectively, implying that these two traits may be genetically independent. This hypothesis was also supported by the colocalization of two functional genes, a starch synthesis gene AGPS2 mapped in QTL CIS_E_07-1 and a starch hydrolysis gene GWD colocated with QTL REC_B_05-1. The cumulative effects of identified QTL were proved to contribute largely and stably to CIS and REC and confirmed with a natural population composed of a range of cultivars and breeding lines. The present research identified reproducible QTL for CIS and REC of potato in diverse conditions and elucidated for the first time their cumulative genetic effects, which provides theoretical bases and applicable means for tuber quality improvement.

Quantitative trait loci for starch-corrected chip color after harvest, cold storage and after reconditioning mapped in diploid potato

“…This finding is in agreement with the results of other studies, where measuring the expression of the genes involved in starch and sugar metabolism in tubers provided markers for AH but not for CS (Neilson et al 2017). Other studies have suggested that tendencies for the accumulation of reducing sugars after CS and RC are genetically independent, and reliable mapping of the QTLs allows dissection of the biological function of each QTL (Xiao et al 2018).…”

“…Mapping of quantitative trait loci (QTLs) has been performed in a number of experimental populations of diploid potatoes (Douches and Freyre 1994;Menendez et al 2002, Werij et al 2012Sołtys-Kalina et al 2015;Śliwka et al 2016;Braun et al 2017;Xiao et al 2018) in addition to a few association studies (Li et al 2008(Li et al , 2010Schreiber et al 2014). The genes involved in starch synthesis and degradation, the Calvin cycle and photorespiration, the glycolysis, oxidative pentose phosphate pathway, and the Krebs cycle are distributed across all twelve potato chromosomes (Chen et al 2001).…”

Healing ofGladioulus grandifloracorms andFusarium oxysporuminfection

“…41,61 The enzymatic darkening is associated with the availability/content of polyphenols 62 PPO and POD activity, 63 Coseteng & Lee, and presence of O2. PPO, present in almost all plant tissues, is composed of four copper atoms and a binding site for two aromatic compounds and O2, catalyzing the O-hydroxylation of O-monophenols in O-diphenols and yielding O-quinones 64 These o-quinones are polymerized with other quinones or phenolics, giving brown, black, brown or red pigments, called melanins, 65,66 as reported for beet, which also underwent darkening of the tissue during healing 23,41 due to the availability of phenolic compounds and increased PPO activity. In potato, the injury caused in the peeling and cutting stages of the sticks breaks the integrity of the membranes and causes the complete oxidation of the substrates by the PPO in the first 10 min after the cellular decompartmentalization.…”

Effect of storage temperature and time on potato cv. Innovator industrial quality

“…However, tubers stored at these temperatures show high sprouting and disease incidence (Wiberley-Bradford et al, 2016). Sprouts turn the tubers physically unsuitable for processing; in addition, the occurrence of sprouting may induce sweetening, resulting in a high sugar content, which is not adequate for processing (Xiao et al, 2018).…”

“…Lower temperatures can be used to delay sprouting (Xiao et al, 2018). However, storage below 8 °C, may increase the darkening after frying, induced by the sweetening of the tubers (Duarte-Delgado et al, 2016).…”