Biotechnology Bulletin ›› 2019, Vol. 35 ›› Issue (1): 35-41.doi: 10.13560/j.cnki.biotech.bull.1985.2018-0763

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Cloning and Functional Analysis of a Potato Ubiquitin-conjugating Enzyme Gene StUBC17

LEI Zhao-xia1, LIU Jing1,2, BAI Yi-ping1, TANG Wei1,2, WANG Hong-yang1,2   

  1. 1. School of Life Science,Yunnan Normal University,Kunming 650500;
    2. Joint Academy of Potato Science,Yunnan Normal University,Kunming 650500
  • Received:2018-09-03 Online:2019-01-26 Published:2019-01-23

Abstract: Ubiquitin-conjugating enzyme E2 is closely correlated with plant growth and disease resistance. To understand the contribution of ubiquitin-conjugating enzyme gene in plant resistance to late blight(Phytophthora infestans),an E2 ubiquitin-conjugating enzyme gene(designated as StUBC17)was cloned from potato cultivar “C88”,and its induced expressions by P. infestans and functions were analyzed. The transcriptions of NbUBC(homolog of StUBC17)was silenced in Nicotiana benthamiana using virus-induced gene silencing(VIGS)method,and the resistance to disease was validated by inoculating P. infestans. Furthermore,the disease-resistant gene and corresponding non-toxic genes of R3a+AVR3a、R3b+AVR3,Rx+CP,and INF1 were transiently expressed in NbUBC-silenced plants. The 447 bp coding region of StUBC17 encoded 148 amino acid residues with 16.52 kD of an estimated molecular mass and 7.72 of a calculated pI. Quantitative reverse transcriptase PCR analysis showed that the expression of StUBC17 was up-regulated after P. infestans infected it. By inoculating leaves in vitro,the identification of disease resistance showed that NbUBC-silenced plants presented an increased susceptibility to P. infestans;however,silencing of NbUBC demonstrated no effect on the hypersensitive responses. Our results suggest that the StUBC17 is necessary for potato plant to defense P. infestans,but its silencing do not affect the R3a-,R3b-,Rx- and INF- triggered hypersensitive responses

Key words: potato, late blight, StUBC17, Nicotiana benthamiana, virus-induced gene silencing