Apple dwarfing rootstocks exhibit an imbalance in carbohydrate allocation and reduced cell growth and metabolism  

作　　者：Toshi M Foster Peter A McAtee Chethi N Waite Helen L Boldingh Tony K McGhie 

机构地区：[1]The New Zealand Institute for Plant and Food Research Limited,Palmerston North,4474,New Zealand [2]The New Zealand Institute for Plant and Food Research Limited,Auckland,1142,New Zealand [3]The New Zealand Institute for Plant and Food Research Limited,Hamilton,3240,New Zealand

出　　处：《Horticulture Research》2017年第1期311-323,共13页园艺研究（英文）

基　　金：This work was funded by the New Zealand Ministry of Business,Innovation and Employment,contract C11X1310;internal funding by The New Zealand Institute for Plant&Food Research Limited.

摘　　要：Apple dwarfing rootstocks cause earlier shoot termination and reduced root and shoot mass.To identify physiological factors responsible for rootstock-induced growth restriction,we compared vascular-enriched gene expression between two dwarfing rootstocks(‘M27’and‘M9’)and the vigorous rootstock‘M793’using RNA sequencing and quantitative reverse transcriptase PCR.Differentially expressed genes common to both dwarfing rootstocks belonged to five main biological processes:(1)primary metabolism,(2)cell wall synthesis and modification,(3)secondary metabolism,(4)hormone signalling and response and(5)redox homeostasis.Genes promoting the biosynthesis of amino acids,lipids and cell walls were downregulated in dwarfing rootstocks,whereas genes promoting the breakdown of these compounds were upregulated.The only exception to this trend was the upregulation of starch synthesis genes in dwarfing rootstocks.Non-structural carbohydrate analysis demonstrated that starch concentrations in‘M9’roots,stems and grafted‘Royal Gala’(‘RG’)scions were double that of equivalent tissues from‘RG’homo-grafted trees(‘RG’/‘RG’).Fructose and glucose concentrations were much lower in all three tissues of the‘RG’/‘M9’trees.Together,these data indicate that dwarfing rootstocks are in a state of sugar depletion and reduced cellular activity despite having large starch reserves.Another significant finding was the over-accumulation of flavonoids and the downregulation of auxin influx transporters MdAUX1 and MdLAX2 in dwarfing rootstocks.We propose that both factors reduce polar auxin transport.The results of this study contribute novel information about the physiological state of dwarfing rootstocks.

关 键 词：walls ROOTS DWARF 

分 类 号：O62[理学—有机化学]