| Due to short storage period,grapes is seriously effected in selling by berry drop,rot,dry rachis,browning in the storage and distribution process.For a long time,Researchers conducted in-depth research about the realtions between ethylene production and berry drop during its storage,and ethylene,which have shown that ethylene plays an important role in grape berry develop ment and organ senescence both before and after harvest.In the biosynthetic pathway of ethylene,ACC synthase is the enzyme that limits ethylene production,which catalyzes the formation of ACC,the immediate precursor of ethylene,and ACS are encoded by members of multigene families,therefore,understanding Vv ACS gene family members spatiotemporal expression characteristics,digging genes rachis-specific or berry-specific during development and senescence of grape rachis and berry would lay a foundation for prolonging shelf and storage life.In order to understand how ACS gene control ethylene synthesis during development and senescence of both the rachis and the berry,the temporal and spatial expression levels of nine ACS genes and the production of ethylene were measured in berry and rachis of two seedless table grape cultivars ‘Thompson Seedless' and ‘Ruby Seedless'.And in this study,rachis-specific Vv ACS1 gene were over-expressed in tomato(Solanum lycopersicum ‘Money maker')by Agrobacterium mediated method.In order to dicuss influences of over-expression of Vv ACS1 gene on tomato,some physiological indexs were analyzed in transgenic tomatos,and functions of Vv ACS1 gene were prelimaryly predicted.The main results were shown as follows:1.During the berry development of Thompson Seedless and Ruby Seedless,we measured the release of ethylene from both the fruit berry and the non-fruit rachis.Detached berries from V.vinifera ‘Ruby Seedless' and ‘Thompson Seedless' showed ethylene release peaks at the beginning of berry development and at veraison,and the ethylene production in the berry was low(0.02-1?L*kg-1 h-1);while ethylene production in the rachis(1-4.5 ?L*kg-1 h-1)was higher than that in the berry and had an obvious peak before harvest in ‘Thompson Seedless'.In both varieties,ethephon treatment induced ethylene production in the rachis but not in the berry,and ethylene production of rachis in ‘Thompson Seedless' was greatly inhibited by AVG treatments.2.Expression of nine VvACS genes showed diverse temporal and spatial patterns in ‘Thompson Seedless' and ‘Ruby Seedless'.The transcriptional level of Vv ACS1 gene in rachis of ‘Thompson Seedless' were spatially,and in ‘Thompson Seedless',expression of Vv ACS1 was detected at the highest level in grape rachis,at a level about thirty times higher than in shoot tip or leaves.For most gene family members,the lowest ACS expression levels were observed in berry and rachis.3.Expression patterns of the VvAC1 gene in rachis during grape berry development and storage showed that,The transcriptional level of Vv ACS1 did significant correlate with ethylene evolution in rachis of ‘Thompson Seedless',which suggested that rachis-specific Vv ACS1 may have important roles in rachis senescing.And Expression levels of most of the ACS genes did not correlate with ethylene released.4.The temporal and spatial expression of Vv ACS1 gene in various tissues showed that Vv ACS1 gene was detected at the highest level in tomato flowers,and there was no abovious expression in leaves.5.The activity of ACC synthase were inhibited at different levels by over-expressing Vv ACS1 gene,and the activity of ACC synthase in the flowers of transgenic tomato was lower than that of non-transgenic.6.Ethylene production of flowers were also inhibited by over-expressing VvACS1 gene,and had significant difference compared with non-transgenic tomato.ethylene release rate of leaves or rachis were also lower than that of non-transgenic,and there were no significant difference.7.Fruit ripening were delayed by over-expression of VvACS1 gene in transgenic tomato. |
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