Key players associated with tuberization in potato: potential candidates for genetic engineering

Abstract

Tuberization in potato (Solanum tuberosum L.) is a complex biological phenomenon which is affected by several environmental cues, genetic factors and plant nutrition. Understanding the regulation of tuber induction is essential to devise strategies to improve tuber yield and quality. It is well established that short-day photoperiods promote tuberization, whereas long days and high-temperatures inhibit or delay tuberization. Worldwide research on this complex biological process has yielded information on the important bio-molecules (proteins, RNAs, plant growth regulators) associated with the tuberization process in potato. Key proteins involved in the regulation of tuberization include StSP6A, POTH1, StBEL5, StPHYB, StCONSTANS, Sucrose transporter StSUT4, StSP5G, etc. Biomolecules that become transported from "source to sink" have also been suggested to be important signaling candidates regulating the tuberization process in potatos. Four molecules, namely StSP6A protein, StBEL5 RNA, miR172 and GAs, have been found to be the main candidates acting as mobile signals for tuberization. These biomolecules can be manipulated (overexpressed/inhibited) for improving the tuberization in commercial varieties/cultivars of potato. In this review, information about the genes/proteins and their mechanism of action associated with the tuberization process is discussed.

Development of pre-breeding diploid potato germplasm displaying wide phenotypic variations as induced by ethyl methane sulfonate mutagenesis

“…Genetic variation in the maturity phenology is of high agronomic interest, especially in regions with a short growing season (Blackman 2017). The observed inability for some lines to tuberize is an evident sign of mutation in one or multiple genes involved in starch synthesis (Muth et al 2008) and mobilization into the tubers (Van Harsselaar et al 2017) as well as in tuber-inducing biomolecules such as gibberellins (Xu et al 1998;Dutt et al 2017), auxins (Roumeliotis et al 2012), phytochrome B (Jackson et al 1998), and sucrose transporter genes (namely, SUT1, SUT2, and SUT4; Chincinska et al 2008). The use of forward genetics by targeting genes involved in important agronomic traits such as starch content and structure, critical photosynthetic genes, or antinutritional factors will help understanding the genetic, molecular, and physiological mechanisms involved in some of the phenotypic variations.…”

Genomic Analyses Yield Markers for Identifying Agronomically Important Genes in Potato

“…The strong selection of GA20ox-1 and CONSTANS is consistent with the critical roles of gibberellic acid and photoperiod in potato tuberization. Many studies have demonstrated that GAdependent and photoperiod-dependent pathways interact to orchestrate the complex tuberization process (Martinez-Garcia et al, 2001;Dutt et al, 2017). GA is required for the elongation of stolon meristems during the initiation of tuberization (Dutt et al, 2017), and knocking down expression of the potato GA20ox-1 gene strongly affects internode elongation, stem length, and tuber induction (Carrera et al, 2000).…”

“…Many studies have demonstrated that GAdependent and photoperiod-dependent pathways interact to orchestrate the complex tuberization process (Martinez-Garcia et al, 2001;Dutt et al, 2017). GA is required for the elongation of stolon meristems during the initiation of tuberization (Dutt et al, 2017), and knocking down expression of the potato GA20ox-1 gene strongly affects internode elongation, stem length, and tuber induction (Carrera et al, 2000). CONSTANS plays an important role in the photoperiodic responses and accelerates flowering time in Arabidopsis (Yano et al, 2000).…”

Genetic mapping of tuber size distribution and marketable tuber yield under drought stress in potatoes

“…The most devastating effects of drought stress on potato occur when water limitation coincides with the tuberization stage of plant development (Daryanto et al 2016). Tuberization in potato involves the differentiation of stolon tips into young tubers (tuber initiation) and the bulking of the young tubers (Catchpole and Hillman 1969;Dutt et al 2017;Minhas et al 2004;O'Brien et al 1998;Ozgen et al 2003). Drought may affect tuberization by reducing the number of tubers that are initiated (Mackerron et al 1988).…”