Differential adaptation of high- and low-chill dormant peaches in winter through aquaporin gene expression and soluble sugar content

Abstract

Plants have their own mechanisms for overcoming various stresses. In cold regions, plants are subject to stress and must enter an inherent dormancy, through several complex mechanisms, if they are to continue to exist. In winter, regulation of tonoplast and plasma membrane aquaporin genes differed in the bud cushions of the high-chill peach (Prunus persica L. Batsch) cv. Kansuke Hakuto and the low-chill peach cv. Coral. In December and January, when the temperature was lowest (around 2 degrees C), the increased expression of Pp-gammaTIP1 and Pp-PIP1 seen in the bud cushions of Kansuke Hakuto may have been related to the concomitant high-soluble sugar content of the cushions of this cultivar. This relationship may have made the cells highly stable and relatively unaffected by low-temperature stress owing to the presence of "glasses" that prevented ice nucleation. However, a simpler form of cold protection regulation seemed to occur in Coral, in which there was no winter increase in Pp-gammaTIP1 and Pp-PIP1 mRNA and a slow decline in total soluble sugar content in December and January. These results suggested that Pp-gammaTIP1 and Pp-PIP1, respectively, play important roles in intra- and intercellular membrane transport, enhancing cold resistance in the bud cushions of high-chill cultivars. In addition, Pp-deltaTIP1 and Pp-PIP2 mRNA increased at the end of endodormancy in both cultivars. This change may be induced by endodormancy-release signals and the resumption of bud activity in both cultivars.

Chilling Requirements and Blooming Dates of Leading Peach Cultivars and a Promising Early Maturing Peach Selection, Momo Tsukuba 127

“…In this paper, we analyzed the relationships between chilling requirements, heat requirements, and blooming dates of the leading peach cultivars in Japan, along with those of Momo Tsukuba 127, for 11 years at NIFTS in Tsukuba and at 24 other locations within the temperate zone of Japan. Because many quantity studies (Topp et al, 2008), genetic or phonologic studies (Yamane et al, 2011;Yooyongwech et al, 2006), and QTL analyses (Fan et al, 2010) of peach chilling requirements have employed the Utah model to determine CU (Richardson et al, 1974), we used this model to determine the chilling requirements in this study.…”

“…Like the 'Okinawa' developed in Florida by Sharpe (1957), 'Okinawa 1' originated from the subtropical Okinawa Island and has a low chilling requirement (Yoshida, 1981). 'Chimarrita' and 'Coral' were developed in Brazil as low-chill genotypes (Topp et al, 2008;Yamaguchi et al, 2007;Yooyongwech et al, 2006). These three low-chill cultivars were used in this experiment as low-chill standards for comparison with Japan's leading peach cultivars and our selection, Momo Tsukuba 127.…”

Molecular aspects of dormancy in peach (Prunus persica [L.] Batsch.)

“…These molecular techniques have been made possible by the progressive identification of genes related to different physiological processes, favoured by the broad application of genomic tools to crop species. A previous use of gene expression markers in the dormancy field was approached by Yooyongwech et al (2009), who measured the mRNA levels of two aquaporins (Pp-γTIP1 and Pp-γPIP1) in high and low-chill varieties, and showed that their increased expression can be used to indicate the state of dormancy release in peach buds. In this work we propose the use of five peach genes as gene expression markers for the evaluation of the dormancy stage of any known or new cultivar in a particular time.…”

Sugar, Starch, and Proline in Peach Trees Exposed to Freezing Temperatures during Dehardening

“…Sugar content was high during the dormant period in January and February, and then decreased until March. A previous study showed that sugar increased in December and gradually dropped from February to April in peach trees [15]. With buds breaking and bursting in late March, sugar content increased.…”

“…15, and Apr. 15,2012 to investigate changes in these metabolites during dehardening (after the endo-dormancy period) in the late winter and the onset of spring conditions. In this study, one-year-old twigs were used, and twigs were collected from 6 twigs from each cultivar.…”