Regulation of sprout growth and translocation of sugars in potato plant tubers that overexpress the PHA1 proton pump of Solanum tuberosum

GROBLY IARA MARLENE; MUÑIZ GARCÍA MARÍA NOELIA; CORTELEZZI JUAN IGNACIO; CAPIATI DANIELA ANDREA

Congreso; XXXIII Argentinian meeting of Plant Physiology (RAFV2021); 2021

Once concluded the dormancy period of potato tubers, begins the development of the sprouts starting the growth cycle of the plant. This process involves a rearrangement of carbohydrate metabolism. From the synthesis of reserve compounds in the tuber (sink), to its degradation, becoming the tuber in a source of sugars that will sustain the development of the sprouts. Plasma membrane H+-ATPases (PM-H+-ATPases) play key roles in plant physiology. They extrude protons out of the cell, generating a membrane potential that provides the driving force for the transport of ions and metabolites through channels and transporters. In potato, it has recently been described the key role of the PHA1 (Solanum tuberosum PM-H+-ATPase 1) in the regulation of plant growth and tuber development. It promotes stolon elongation and tuber growth, regulating the sucrose-starch metabolism and transport.In this work we studied the StPHA1 role in the sprout growth and carbohydrate levels of sprouts and sprouted tubers, using potato plants (Solanum tuberosum Spunta) that constitutively and ubiquitously overexpress this gene (PHA1-OE plants). Transgenic plants showed longer sprouts, lower levels of soluble sugars and starch in the sprouted tubers, and lower levels of soluble sugars and higher levels of starch in the tuber sprouts, compared to wild type plants. Concluding, the activity of PHA1 would be energizing the apoplastic transport of sucrose from the tuber to the sprout during its growth, favoring an accumulation of sugars in the high-growth tissue.