Down-regulation of POLYGALACTURONASE1 alters firmness, tensile strength and water loss in apple (Malus x domestica) fruit

BMC Plant Biology

Research Article

David A Brummell¹  Ross G Atkinson²  Paul W Sutherland²  Jason W Johnston²  Deepali Mitra²  Ian C Hallett²  Roswitha Schröder²  Sarah L Johnston²  Kularajathevan Gunaseelan²  Robert J Schaffer³ 

[1] PFR, Food Industry Science Centre, Private Bag, 11600, Palmerston North 4442, New Zealand;The New Zealand Institute for Plant & Food Research Limited (PFR), Mount Albert Research Centre, Private Bag, 92169, Auckland 1142, New Zealand;The New Zealand Institute for Plant & Food Research Limited (PFR), Mount Albert Research Centre, Private Bag, 92169, Auckland 1142, New Zealand;The University of Auckland, Private Bag, Auckland 1142, 92019, New Zealand;

关键词: Malus;    Fruit softening;    Intercellular adhesion;    Polygalacturonase;    Texture;    Pectin;   

DOI  :  10.1186/1471-2229-12-129

 received in 2012-04-23, accepted in 2012-07-25,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundWhile there is now a significant body of research correlating apple (Malus x domestica) fruit softening with the cell wall hydrolase ENDO-POLYGALACTURONASE1 (PG1), there is currently little knowledge of its physiological effects in planta. This study examined the effect of down regulation of PG1 expression in ‘Royal Gala’ apples, a cultivar that typically has high levels of PG1, and softens during fruit ripening.ResultsPG1-suppressed ‘Royal Gala’ apples harvested from multiple seasons were firmer than controls after ripening, and intercellular adhesion was higher. Cell wall analyses indicated changes in yield and composition of pectin, and a higher molecular weight distribution of CDTA-soluble pectin. Structural analyses revealed more ruptured cells and free juice in pulled apart sections, suggesting improved integrity of intercellular connections and consequent cell rupture due to failure of the primary cell walls under stress. PG1-suppressed lines also had reduced expansion of cells in the hypodermis of ripe apples, resulting in more densely packed cells in this layer. This change in morphology appears to be linked with reduced transpirational water loss in the fruit.ConclusionsThese findings confirm PG1’s role in apple fruit softening and suggests that this is achieved in part by reducing cellular adhesion. This is consistent with previous studies carried out in strawberry but not with those performed in tomato. In apple PG1 also appears to influence other fruit texture characters such as juiciness and water loss.

【 授权许可】

Unknown   
© Atkinson et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.