Interaction of ascorbic acid and gibberellins in the establishment of tomato fruits

ALEGRE, MATÍAS LEONEL; BALDET, PIERRE; ROTHAN CHRISTOPHE; BRÈS, CÉCILE; JUST, DANIEL; OKABE, YOSHIHIRO; EZURA, HIROSHI; GERGOFF GROZEFF, GUSTAVO ESTEBAN; BARTOLI, CARLOS GUILLERMO

Rosario

Congreso; XXXIV Argentinian Meeting of Plant Physiology RAFV Conference 2023; 2023

SOCIEDAD ARGENTINA DE FISIOLOGIA VEGETAL

Tomato fruit have a great economic and nutritional importance for human beings. The number of fruits per plant is the most important factor determining the yield of tomato crops. This factor depends on the efficiency of fruit set and is a consequence of successful pollination and fertilization. Gibberellins (GA) have been found to play a very important role in promoting pollen tube growth and the onset of fruit growth. Tomato mutants (slggp1) deficient in GDP L galactose phosphorylase activity, a key enzyme in the ascorbic acid (AA) synthesis pathway, have lower GA concentrations in the flowers and a lower percentage of fruit set. AA plays a central role in the antioxidant defense of plants and numerous other functions, among which we will highlight its role as an enzymatic cofactor in the synthesis of GA and its participation in the regulation of cell division and expansion. To determine the mechanisms and signals triggered by GA and AA in fruit set and pollen grain growth, slggp1 mutants deficient in AA and a wild type were used. These plants were periodically sprayed with GA3 and paclobutrazol (PBZ, an inhibitor of GA synthesis). The PBZ treatment decreased the percentage of fruit set in the mutant genotypes but not in the wild type plants and the GA treatment increased the percentage of fruit set, similar in both mutant and wild type. The pollen tubes of the mutant genotypes have a lower in vitro growth rate. The GA content (GA1, GA3, GA4 y GA8) as well as the expression of key genes in the gibberellin synthesis, degradation and signaling mechanism were analyzed in gynoecia of pre anthesis, anthesis flowers, and 2 4 mm fruits. From these preliminary results, it can be assumed that there is an interaction between a signaling molecule such as GA with AA levels, which could be a new contribution to the complex signaling process involved in the establishment and initiation of fruit growth.