Apple SEPALLATA1/2‐like genes control fruit flesh development and ripening. (20th February 2013)

• Record Type: Journal Article
• Authors: Ireland, Hilary S.; Yao, Jia‐Long; Tomes, Sumathi; Sutherland, Paul W.; Nieuwenhuizen, Niels; Gunaseelan, Kularajathevan; Winz, Robert A.; David, Karine M.; Schaffer, Robert J.
• Is Part Of: Plant journal. Volume 73:Number 6(2013:Mar.)
• Page Start: 1044
• Page End: 1056
• Publication Date: 2013-02-20
• Subjects: Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.12094
• Languages: English
• ISSNs: 0960-7412

Abstract

<abstract abstract-type="main" xml:lang="en" id="tpj12094-abs-0001"> <title>Summary</title> <p>Flowering plants utilize different floral structures to develop flesh tissue in fruits. Here we show that suppression of the homeologous <italic>SEPALLATA1/2</italic>‐like genes <italic>MADS8</italic> and <italic>MADS9</italic> in the fleshy fruit apple (<italic>Malus</italic> x <italic>domestica</italic>) leads to sepaloid petals and greatly reduced fruit flesh. Immunolabelling of cell‐wall epitopes and differential staining showed that the developing hypanthium (from which the apple flesh develops) of <italic>MADS8/9</italic>‐suppressed apple flowers lacks a tissue layer, and the remaining flesh tissue of fully developed apples has considerably smaller cells. From these observations, it is proposed that <italic>MADS8</italic> and <italic>MADS9</italic> control the development of discrete zones within the hypanthium tissue, and therefore fruit flesh, and also act as foundations for development of different floral organs. At fruit maturity, the <italic>MADS8/9</italic>‐suppressed apples do not ripen in terms of both developmentally controlled ripening characters, such as starch degradation, and ethylene‐modulated ripening traits. Transient assays suggest that, like the <italic>RIN</italic> gene in tomato, the <italic>MADS9</italic> gene acts as a transcriptional activator of the ethylene biosynthesis enzyme, 1‐aminocyclopropane‐1‐carboxylate (ACC) synthase 1. The existence of a single class of genes that regulate both flesh formation and ripening provides an evolutionary tool for controlling two critical aspects of fleshy fruit development.</p> </abstract>