Changes Of Omics After Paulownia Trees Infected By The Paulownia Witches Phytoplasma Pathogen

Paulownia Witches Broom(PaWB)is caused by phytoplasma(Candidatus Phytoplasma australiense).PaWB,a disastrous disease,the incidence arrived 85%in some cultivation district of China and other parts of the world,which has brought much economic damage.Thus,it's important to dissect the molecular mechanism of Phytopathogens-Paulownia interaction in breeding resistance varieties.In the present study,many of genes,miRNAs and proteins that related to PaWB had been analyzed by transcriptome,miRNA,drgradome and proteome in Paulownia fortunei,P.tomentosa and P.tomentosa ×P.fortunei species.The main results as follow:(1)A total of 27024 transcripts had been obtained from six libraries by using the Illumina sequencing.Among these transcripts,23132 transcripts were common in the three healthy Paulownia libraries,and 25160,24562 and 24426 were identified in the PF,PT and PTF libraries,respectively.In addition,23176 transcripts were common in the three healthy Paulownia libraries,and 25106,24625 and 25065 were identified in the PFI,PTI and PTFI libraries,respectively.We performed differential expression analysis of the identified transcripts between the healthy and PaWB-infected Paulownia plants,a total of 3563,1274,and 2671 differentially expressed transcripts(DEG)were found in the P.fortunei,P.tomentosa and P.tomentosa×P.fortunei,respectively.Meanwhile,the number of the DEGs in the hybrid P.tomentosa ×P.fortunei is half of that in its parents.(2)In three Paulownia species,186 DEGs with the same expressed trends had been identified,and eight genes include disease resistance protein RPM1,serine/threonine-protein kinase PBS1,transcription factor MYC2,calcium-binding protein CML,transcription factor WRKY,cytokinin-regulated kinase and putative receptor-like serine-threonine protein kinase were involved in the disease stress.Additionally,10 DEGs which encoded the solute carrier protein that highly expressed in the infected paulownia were identified.The DEGs in three paulownia species were mainly involved in the plant-pathogen interaction,plant hormone signal transduction,phenylpropanoid biosynthesis,flavonoid biosynthesis,phenylalanine metabolism,flavone and flavonol biosynthesis and regulation of actin cytoskeleton metabolism.(3)In this present study,781 miRNAs(458 conserved and 323 novel miRNAs)had been identified in three Paulownia species.Among them,310 miRNAs(204 conserved and 106 novel miRNAs),422 miRNAs(245 conserved and 177 novel miRNAs)and miRNAs(257 conserved and 99 novel miRNAs)were obtained in the P.fortunei,P.tomentosa and P.tomentosa ×P.fortunei,respectively.There were less diversity miRNA members that common between the hybrid P.tomentosa×P.fortumei and its male parent(13)than that in the female parent(99).A total of 473 differentially expressed miRNAs were identified,and seven of them were common in the three paulownia species.These miRNAs play the important roles in the phenylpropanoid biosynthesis,plant-pathogen interaction,peroxisome,ABC transporters,porphyrin and chlorophyll metabolism and oxidative phosphorylation metabolism.(4)In the fortunei,236 significant differentially abundant proteins were obtained,and 28 of which were correlated with the transcripts;192 significant differentially expressed proteins had been obtained in the P.tomentosa,and 13 of them were correlated with the transcripts.Of these,12 differentially expressed(correlated with transcripts)were common in the PFI vs.PF and PTI vs.PT comparison.Most differentially abundant proteins were closely related to plant-pathogen interaction,carbon fixation in photosynthetic organisms,photosynthesis,porphyrin and chlorophyll metabolism,pentose phosphate pathway and oxidative phosphorylation etc,,such as thiamine biosynthetic enzyme,chitinase,lipoxygenase,polyphenol oxidase,elongation factor Tu,heat shock protein,ATP-dependent DNA helicase HFM1/MER3,calcium-binding protein,ribulose-1,5-bisphosphate carboxylase/oxygenase,and solute carrier family 50(sugar transporter).(5)Four DEGs related the PaWB(transcription factor MYC2,serine/threonine-protein kinase PBS1,transcription factor bHLH87-like and,peroxidase)were cloned.The expression profiles of them in three paulownia species were analyzed using qRT-PCR assays.