Integrated analysis of transcriptome, small RNA, and phytohormonal content changes between Artemisia annua Linn. and Nicotiana benthamiana Domin in heterogeneous grafting

Abstract

Grafting, one of the artificial propagation methods used in plants, is now widely used in flower breeding, vegetable cultivation and stress response research. In order to discover the reason for success of heterograft and information exchange mechanisms, we used Artemisia annua (Aa) as scion and Nicotiana benthamiana (Nb) as rootstock to build a grafting model. After grafting 30 days co-growth, 7,794 DEGs (different expression genes) and 8,214 DEGs were identified in Aa scion and Nb rootstock, respectively. Most of the DEGs belong to defense response and signal transduction in scion and substance metabolism in rootstock, which indicate that the diverging response mechansim of grafted parts. Fifty Nb genes and 20 Aa genes were detected in Aa scion and Nb rootstock, which were regarded as potentially active genes during the grafting process. The most abundant miRNAs are miR159 and miR166, which may be closely related to their conservation and physiological functions. Besides, miR159 and miR166 could quickly respond to internal change, therefore the two miRNAs should be considered as biomarkers of successful grafting models. And then, as simultaneously screened miRNAs, miR396 and miR6149 could be potential biomarker in Aa and Nb, respectively. Through the analysis of the miRNA-target gene network in differentially expressed miRNAs, transcription factor R2R3-MYB, bHLH, GRAS, GAMYB, SBP-box, MADS-box, IIS in scion and NF-Y in rootstock were regarded as key genes involved in growth and development of grafted plants. The content of ABA, JA, CK was calculated in grafted plants and showed its respective functions.

Keywords

• artemisia annua
• graft
• mrna
• mirna
• nicotiana benthamiana
• phytohormone