Changes in aquaporin gene expression and magnetic resonance imaging of water status in peach tree flower buds during dormancy

Abstract

The movement of cellular water accompanies changes in growth within dormant buds. To further understand this process, accumulation of tonoplast deltaTIP1 and plasma membrane PIP2 aquaporin transcripts was measured by quantitative reverse transcriptase-polymerase chain reaction and the water dynamics in dormant peach (Prunus persica L.) flower buds was studied by magnetic resonance imaging. Proton density (PD), spin-spin relaxation time (T(2)) and apparent diffusion coefficient (ADC) were used to observe water dynamics during dormancy. The expression of deltaTIP1 and PIP2 aquaporins, PD and T(2) in the upper part of the bud including primordia, in the basal part of the bud and the bud trace increased earlier in the low-chill cultivar 'Coral' than in the high-chill cultivar 'Kansuke Hakuto,' reflecting the difference in timing for the end of endodormancy in the two cultivars. deltaTIP1 mRNA accumulated mainly in the basal part of the bud, whereas PIP2 mRNA was detected mainly in the upper part. These findings may reflect the activation of inter- and intracell communication through membrane transport properties of aquaporins resulting in a gradual increase in water content to that required for bud activity at the end of endodormancy. An apparent decrease in the expression of deltaTIP1 and PIP2 mRNAs was, however, observed in late winter in some portions of the buds of both cultivars just before sprouting.

Regulation of Bud Dormancy and Bud Break in Japanese Apricot (Prunus mume Siebold ^|^amp; Zucc.) and Peach [Prunus persica (L.) Batsch]: A Summary of Recent Studies

“…Since sugar concentrations remained high during cold deprivation, bud necrosis caused by cold deprivation could be the consequence of an inability to use carbohydrate reserves. Another example of a biochemical study was the analysis of seasonal changes of the water status of peach flower buds by magnetic resonance imaging (Yooyongwech et al, 2008). Surprisingly, there have only been a few studies on the analysis of phytohormone contents during dormancy transition in Prunus.…”

Study of the Consequences of Global Warming in Water Dynamics During Dormancy Phase in Temperate Zone Fruit Crops

“…The relaxation time measured in flower buds is an indicator of the physiological development of ecodormancy because of water absorption (Sugiura et al, 1995). Peach cultivars with lower chilling requirement increased both T2 and PD after release of dormancy, which occurred earlier compared to high-chill cultivars (Yooyongwech et al, 2008b). Water transport in twigs of Picea was firstly slow during winter season and then increased relatively fast in early spring (de Fay et al, 2000).…”

“…7, 8, 9). Yooyongwech et al (2008b) reported that oscillation temperature conditions accelerate water movement in peach buds, but promoted an irregular bud growth. The effect of consecutive seasons of mild winter (CS) on reduction of water mobility and content in bud scales was also observed by a more accentuated reduction on signal intensity (Yamamoto et al, 2010a).…”

“…seedlings were detected by acoustic emission coupled with magnetic resonance microscopy, respectively. NMR and MRI has been used to provide details during cold acclimatization and/or dormancy stage control in organs and tissues of several species, such as in dogwoods (Burke et al, 1974), Norway spruces (de Fay et al, 2000), tulip bulbs (Kamenetsky et al, 2003;Van der Toorn et al, 2000b), hybrid poplars (Kalcsits et al, 2009), blueberries (Parmentier et al, 1998;Rowland et al, 1992), grapes (Fennell & Line, 2001;Gardea et al, 1994), peaches (Erez et al, 1998;Sugiura et al, 1995;Yooyongwech et al, 2008b), Japanese pears (Yamamoto et al, 2010a), apples Liu et al, 1993;Millard et al, 1993;Snaar & Van As, 1992), among others.…”

Virus-induced Gene Silencing in Apricot (Prunus armeniaca L.) and Japanese Apricot (P. mume Siebold ^|^amp; Zucc.) with the Apple Latent Spherical Virus Vector System

“…Three technical replicates were performed. As a reference, the UBIQUITIN gene-specific primer pair PavUbi-F and PavUbi-R (Yooyongwech et al, 2008; AF298826; Table 1) was used for RT-PCR and real-time RT-PCR analyses.…”