; Tieman and Handa, 1994 ; Tieman et al., 1992 ; Watson et al., 1994 ). Recently, expansin (EXP), a nonenzymatic protein, was found to play an important role in cell wall loosening and extension. Expansin was first discovered while researching the “acid
Shaolan Yang, Changjie Xu, Bo Zhang, Xian Li, and Kunsong Chen
Zhengke Zhang, Runshan Fu, Donald J. Huber, Jingping Rao, Xiaoxiao Chang, Meijiao Hu, Yu Zhang, and Nina Jiang
fully prevented fruit softening in many cases ( Goulao and Oliveira, 2008 ). Expansins are nonenzymatic cell wall-localized proteins that were first isolated from cucumber hypocotyl walls by analysis of pH-dependent cell-wall extensibility ( McQueen
Sang-Dong Yoo, Zhifang Gao, Claudio Cantini, Wayne H. Loescher, and Steven van Nocker
A preliminary understanding of developmental processes among divergent species is essential to evaluate the applicability of information from model species to plants of agricultural importance. In tomato (Lycopersicon esculentum Mill.), where the molecular biology associated with fruit ripening has been studied most extensively, tissue softening is due at least in part to the activity of proteins called expansins, in concert with enzymatic activities that modify the pectin and xyloglucan components of the cell wall. We evaluated the potential for the concerted action of expansins and other cell wall-modifying enzymes during ripening in a highly divergent fruit species, sour cherry (Prunus cerasus L.). We identified a family of four expansin genes that was strongly upregulated at the advent of ripening. Activation of these genes was accompanied by strong upregulation of gene(s) encoding potential pectin methylesterases, pectate lyase(s), and xyloglucan endotransglycosylase(s). Initiation of ripening and gene induction were also associated with a rapid decrease in cell wall weight. These results suggest that expansin and several other distinct activities could be involved in ripening-associated cell wall modification in cherries.
Jing Ma, Zheng Li, Bin Wang, Shunzhao Sui, and Mingyang Li
Expansin is a cell wall protein, which is a regulatory factor of cell growth. It plays an important role in plant cell wall extension ( Lee et al., 2001 ; Li et al., 2003 ; McQueen-Mason et al., 1992 ). However, the plant cell wall is a complex
Yu-Xiong Zhong, Jian-Ye Chen, Hai-Ling Feng, Jian-Fei Kuang, Ruo Xiao, Min Ou, Hui Xie, Wang-Jin Lu, Yue-Ming Jiang, and He-Tong Lin
), polygalacturonases (PGcase), pectate lyase, and pectin methyl esterase (PME), are involved in cellular-wall degradation ( Rose and Bennett, 1999 ). Recently, expansin and xyloglucan endotransglucosylase/hydrolase (XET/XTH) have been suggested to be involved in fruit
Alexander G. Litvin, Marc W. van Iersel, and Anish Malladi
., 2011 ). Loosening of the cell wall to increase plasticity and the presence of adequate turgor pressure are key factors that facilitate cell expansion ( Cosgrove et al., 2002 ). Cell wall extensibility is affected by multiple enzymes, including expansins
Zhencai Wu and Paul A. Wiersma
Expansins are a class of proteins that stimulate the extension of plant cell walls. Expansins have been found in nearly all growing plant tissues, such as hycopotyls, young seedlings, fibers, internodes, flower petals, and ripening fruits. We isolated two full-length expansin cDNA clones, Pruav-Exp1 and Pruav-Exp2, from sweet cherry (Prunus avium L.) fruit. Pruav-Exp1 has 1048 nucleotides encoding 254 amino acids, while Pruav-Exp2 has 1339 nucleotides encoding 250 amino acids. Deduced amino acid sequences of sweet cherry Pruav-Exp1 and Pruav-Exp2 share 72% identity. A Blast search of the GenBank database with the deduced amino acid sequences of Pruav-Exp1 and Pruav-Exp2 indicated a high sequence identity with other plant expansin genes. Interestingly, Pruav-Exp1 shares 99% identity of amino acid sequence with that of apricot expansin Pav-Exp1. Fragments from the 3' ends of Pruav-Exp1 and Pruav-Exp2 were cloned to generate gene-specific probes. These probes were used to study expansin gene expression in different tissues and during fruit development. Northern blot analysis showed different mRNA expression patterns for each gene. The mRNA of Pruav-Exp1 was expressed at the pink and ripe stages, but not at the early green and yellow stages of fruit development. The mRNA of Pruav-Exp2 was present earlier, from a low level in yellow expanding fruit, increasing to a high level at the pink stage and remaining at this level through the ripe stage. Both mRNAs were also expressed at a low level in flower, but not present in other tissues such as roots, leaves and peduncles. Our study indicates an expansin gene family is present in sweet cherry and suggests that two expansin genes may have different roles during fruit development and ripening.
Wang Yong, Lu Wangjin, Li Jianguo, and Jiang Yueming
To understand the relationship between fruit cracking and gene expression patterns, we identified two expansin genes from litchi (Litchi chinensis Sonn.) fruit and then examined their expression profiles in pericarp and aril at different stages of fruit development, using the cracking-resistant cultivar Huaizhi and the cracking-susceptible cultivar Nuomici. Two full-length cDNAs of 1087 and 1010 base pairs encoding expansin, named LcExp1 and LcExp2, were isolated from expanding fruit using RT-PCR and RACE-PCR (rapid amplification of cDNA ends) methods. LcExp1 mRNA could be detected from the early stage of fruit rapid growth (59 days after anthesis). The LcExp1 mRNA increased and reached to the highest level at the end of growth phase (80 days after anthesis) in pericarp of `Huaizhi', while the mRNA could be detected at the stage of rapid fruit growth, then increased slightly and finally kept remained almost constant in the pericarp of `Nuomici'. Similar accumulation of LcExp2 mRNA was observed in fruit aril of `Nuomici' and `Huaizhi', whereas LcExp2 accumulated only in pericarp of `Huaizhi' but did not appear in pericarp of `Nuomici'. The results indicate that expression of two expansin genes in litchi pericarp are closely associated with fruit growth and cracking.
Madhumita Dash, Lisa Klima Johnson, and Anish Malladi
al., 2006 ; Li et al., 2003 ). In tomato, two putative cobra-like genes are present within a quantitative trait locus ( fw3.2 ) associated with the control of fruit weight ( Zhang et al., 2012 ). The α−type expansin genes encode for proteins
Madhumita Dash, Lisa K. Johnson, and Anish Malladi
-type cyclins ( CYCs ) are positively associated, whereas others such as the KIP related proteins, MdKRP4 and MdKRP5 , are negatively associated with cell production during different stages of apple fruit growth ( Malladi and Johnson, 2011 ). Expansins