| Eucalyptus grandis,natural distributed in New South Wales Newcastle,central Queensland Bundaberg,and Northern Queensland,Townsville and Danteli and other coastal or near coastal areas,became the preferred breeding materials by Eucalyptus breeders owing to its widely adaptability and excellently processing characteristics.In the paper,8 seedlots of E.grandis plantation in 2010 were selected,and 100 species,which the main characters could be stable hereditary,were selected for the final research objects,according to the theory of core germplasm pool construction.The study mainly carried out from following aspects.Firstly,it was systematically studied the growth,stem form evaluation,leaf characteristics,wood property,the harmnesss of Leptocybe invasa,related enzyme activity after L.invasa infecting,sugar content and volatile compounds content in leaves of E.grandis.Secondary,the genome-wide association analysis was studied based on Illumina HiSeqTM sequencing data.Thirdly,three strains of high sensitivity and high resistance vegetative propagation materials,respectively,screened out by the results of investigation and evaluation on the harmness of L.invasa,were used to study on the resistance of L.invasa.Finally,a comprehensively explore of the resistance mechanism to L.invasa was researched by integrating of physiological,biochemical and metabolic data as well as transcriptome data.The main conclusions were as follows:1.The growth among E.grandis seedlots was not significantly different.The height of 6 year old E.grandis was from 15.00 m to 17.02 m,first banch height was from 6.83 m to 8.70 m,diameter at breast height was from 11.28 cm to 14.21 cm,and the individual volume was from 0.08m3 to 0.15 m3,crown width was from 1.56 m to 1.86 m,stem straightness was from 3.30 to 3.86,crown-fullness ratio was from 2.20 to 3.21,branch was from 1.60 to 2.86 and branching angle was from 47.69° to 62.50°.The difference between single strains was significant,single plant selection was effective,and No.74 finally selected by principal component analysis,with the score of 1.6.2.The basic density was from 0.38 g.cm-3 to 0.44 g.cm-3,with an average of 0.42 g.cm-3;The proportion of vessel was from 10.06% to 12.18% with an average of 11.00%;the parenchyma proportion was from 2.46% to 2.55% with an average of 2.51%;the proportion of wood ray was from 12.89% to14.73% with an average of 13.84%;the wood fiber width was from 7.39 ?m to 7.90 ?m with an average of 7.62 ?m;the wood fiber length was from 891.81 ?m to 976.36 ?m with an average of 932.95 ?m;the wood fiber length to width ratio was from 107.02 to 181.40 with an average of 124.77;and the microfibril angle was from 16.22° to 18.48° with an average of 17.42°.Basic density,parenchyma proportion,wood fiber proportion,fiber width,fiber length and fiber L/W ratio were increased gradually from pith to bark,however,parenchyma proportion,wood ray proportion and microfibril angle were reduced.3.The investigation of the damage of L.invasa found that,seedlots 16892,17907,20555 and 20674 had two high sensitive strains,respectively;seedlots18146,20261 and South Africa had one high sensitive strain,respectively;and the seedlot 18705 had four high sensitive strains.There were 41 highest resistance strains in total.4.Defensive enzymes in different seedlots was different,but not significant.PPO,CAT,POD enzyme activity in different plants were significant difference,but SOD enzyme activity was not significant.There was no significant difference in chlorophyll b content between seedlots and individuals,and there was no significant difference in chlorophyll a and carotenoid content among seedlots.5.The main volatile components of E.grandis leaves were monoterpene,and the relative content was above 80%.The relative content of monoterpene alcohols was significantly with changing in the range of 6.27% ~ 11.79%,and the relative content of monoterpene alcohols of provenances 18146,18705,20261 and S.Africa were above 10%.The largest relative content of monoterpene was No.17,which up to 96.87%,and its main ingredients were alpha pinene(57.94%),gamma Terpinene(22.80%)and p-cymene(10.46%);However,The largest relative content of monoterpene alcohols was NO.96,Its content was up to 44.39%,and the main components were 1,8-cineole(42.20%),alpha pinene(31.68%)and p-cymene(16.52%).6.GWAS analysis of main characters of E.grandis found that there were 15 SNP and 51 genes,associating with L.invasa,located in eight chromosomes frame.The annotations of candidate genes were mainly related with plant resistance,adaptation to stress environment,disease defense,respiration and photosynthesis,etc.Three sites found associated with clear bole height,one site associated with specific leaf area,six sites were associated with crown width and four sites found associated with wood fiber proportion.7.The resistant transcriptome of L.invasa found 579 differentially expressed genes.Compared with high resistant varieties,360 genes were up-regulated and 219 genes were down-regulated in the high sensitivity varieties.There were 244 differentially expressed genes in GO enrichment and the most abundant genes were defense related genes,which including 32 differentially expressed genes.In the GO enrichment analysis,eight most important nodes of molecular function enrichment were protein binding,sesquiterpene synthase activity,ubiquitin protein ligase with binding,guanylate cyclase activity,enzyme inhibitor activity,histone methyltransferase activity,myrcene synthase activity and ocimene synthase activity.8.The integration of L.invasa revealed that lipid transfer enzyme(VAS)was significantly down regulated in high resistant cultivars,and the results were consistent with those of cucumber and pepper.There were 92 TPS family members in Eucalyptus,which had a significant expansion compared with arabidopsis.There were 13 EgrTPS genes up-regulated and 14 genes was significantly down regulated in resistant and susceptible varieties.These genes may be closely related to the difference of insect resistance of Eucalyptus,but their functions need to be further studied. |
PDF Full Text Request