Identification of 1-aminocyclopropane-1-carboxylic acid synthase genes controlling the ethylene level of ripening fruit in Japanese pear (Pyrus pyrifolia Nakai)

Abstract

The shelf life of Japanese pear fruit is determined by its level of ethylene production. Relatively high levels of ethylene reduce storage potential and fruit quality. We have identified RFLP markers tightly linked to the locus that determines the rate of ethylene evolution in ripening fruit of the Japanese pear. The study was carried out using sequences of two types of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase genes (PPACS1 and pPPACS2) and a ACC oxidase gene (PPAOX1) as probes on 35 Japanese pear cultivars expressing different levels of ethylene (0.0 to approximately 300 microl/kg fresh weight/h) in ripening fruit. When total DNA was digested with HindIII and probed with pPPACS1, we identified a band of 2.8 kb which was specific to cultivars having very high ethylene levels (> or = 10 microl/kg f.w./h) during fruit ripening. The probe pPPACS2 identified a band of 0.8 kb specific to cultivars with moderate ethylene levels (0.5 microl/kg f.w./h-10 microl/kg f.w./h) during fruit ripening. The cultivars that produce high levels of ethylene possess at least one additional copy of pPPACS1 and those producing moderate levels of ethylene have at least one additional copy of pPPACS2. These results suggest that RFLP analysis with different ACC synthase genes could be useful for predicting the maximum ethylene level during fruit ripening in Japanese pear.

The fading distinctions between classical patterns of ripening in climacteric and non-climacteric fruit and the ubiquity of ethylene—An overview

“…h −1 during ripening (Itai et al 2002). Differences in the ethylene production were thought to be regulated mainly by differential expression of ethylene biosynthetic genes of ACCsynthase (Itai et al 1999;2002; Ripening behaviour of some attached and detached fruits Many fruits that belong to climacteric group such as apple and pear enter the climacteric phase soon after harvest but they might not ripe fully for weeks if left on the tree (Gerhardt 1947). The best example for such a differential behaviour is the avocado fruit.…”

Molecular Characterization of Pear 1-Aminocyclopropane-1-Carboxylate Synthase Gene Preferentially Expressed in Leaves

“…Through PpACS1 protein, there are only one N-glycosylation site (PGSs; N in NxS/T motifs, positions 422) and cAMP-and cGMP-dependent protein kinase phosphorylation site (R 307 RMS 310 ). Sequence comparison revealed that PpACS1 shares the highest similarity (97% identity) with PcACS2b (El-Sharkawy et al, 2004) and pPPACS2 (Itai et al, 1999). It shares relatively high homology (96% identity) with MdACS3a-1 and MdACS3a-2, but relatively low homology (83-95% identities) with pPPACS1 (Itai et al, 1999) and other known plant ACSs (Fig.1).…”

“…Sequence comparison revealed that PpACS1 shares the highest similarity (97% identity) with PcACS2b (El-Sharkawy et al, 2004) and pPPACS2 (Itai et al, 1999). It shares relatively high homology (96% identity) with MdACS3a-1 and MdACS3a-2, but relatively low homology (83-95% identities) with pPPACS1 (Itai et al, 1999) and other known plant ACSs (Fig.1). This conserved structure may be related to the maintenance of ACS functions for plant development.…”

“…As shown in Fig.3, these proteins obviously split into two subgroups. PpACS1, PcACS2b (El-Sharkawy et al, 2004), PcACS2a (El-Sharkawy et al, 2004, pPPACS2 (Itai et al, 1999), MdACS3a-2, MdACS3a-1, MdACS3c (Wang et al, 2009), PcACS3a, MdACS3b (Wang et al, 2009) and AtACS7 (Mayer et al, 1999) form one subgroup, while PbACS1B, pPPACS1 (Itai et al, 1999) and PcACS1b (El-Sharkawy et al, 2004) together with the Arabidopsis ACS8 are located in the second branch of the tree. These results suggest that the divergence could have occurred before the differentiation of the plants.…”

“…Lots of important ACC synthase genes have been isolated and characterized from the plant kingdom. For examples, ACS genes were identified in pear (Pyrus communis) (El-Sharkawy et al, 2004), Japanese pear (Pyrus pyrifolia) (Itai et al, 1999), apple (Rosenfield et al, 1996;Wang et al, 2009), peach (Mathooko et al, 2001;Tatsuki et al, 2006), pineapple (Cazzonelli et al, 1998;Botella et al, 2000;Trusov et al, 2006), plum (El-Sharkawy et al, 2008), cucumber (Mathooko et al, 1999), watermelon (Salman-Minkov et al, 2008), Arabidopsis (Rodrigues-Pousada et al, 1993;Mayer et al, 1999) , tomato (Nakatsuka et al, 1997), etc.…”