Abstract
Plant cells enhance the tolerances to abiotic and biotic stresses via recognition of the stress, activation and nuclear import of signaling factors, up-regulation of defense genes, nuclear export of mRNA and translation of defense proteins. Nuclear pore-mediated transports should play critical roles in these processes, however, the regulatory mechanisms of nuclear-cytoplasmic transport during stress responses are largely unknown. In this study, a regulator of nuclear export of RNA and proteins, NbRanBP1-1 (Ran-binding protein1-1), was identified as an essential gene for the resistance of Nicotiana benthamiana to potato blight pathogen Phytophthora infestans. NbRanBP1-1-silenced plants showed delayed accumulation of capsidiol, a sesquiterpenoid phytoalexin, in response to elicitor treatment, and reduced resistance to P. infestans. Abnormal accumulation of mRNA was observed in NbRanBP1-1-silenced plants, indicating that NbRanBP1-1 is involved in the nuclear export of mRNA. In NbRanBP1-1-silenced plants, elicitor-induced expression of defense genes, NbEAS and NbWIPK, was not affected in the early stage of defense induction, but the accumulation of NbWIPK protein was reduced. Nuclear export of the small G-protein NbRan1a was activated during the induction of plant defense, whereas this process was compromised in NbRanBP1-1-silenced plants. Silencing of genes encoding the nuclear pore proteins, Nup75 and Nup160, also caused abnormal nuclear accumulation of mRNA, defects in the nuclear export of NbRan1a, and reduced production of capsidiol, resulting in decreased resistance to P. infestans. These results suggest that nuclear export of NbRan is a key event for defense induction in N. benthamiana, and both RanBP1-1 and nucleoporins play important roles in the process.
Highlights
IntroductionSolanaceae plants include many economically important crops such as Solanum (potato, tomato, and eggplant), Capsicum (chili and bell peppers), and Nicotiana (tobacco) species
Solanaceae plants include many economically important crops such as Solanum, Capsicum, and Nicotiana species
Short cDNA fragments were generated from mRNA of N. benthamiana leaves treated with the elicitor INF1, a secretory elicitor protein produced by P. infestans (Kamoun et al, 1997), and subsequently inserted into the pTV00 vector (Ratcliff et al, 2001)
Summary
Solanaceae plants include many economically important crops such as Solanum (potato, tomato, and eggplant), Capsicum (chili and bell peppers), and Nicotiana (tobacco) species. One critical problem for potato production is the control of late blight disease caused by the oomycete pathogen. Potato late blight is known as a causal agent of the Irish “Great famine” in the 1840s, and even today, annual cost for yield losses and control efforts in developing countries are estimated around 9 billion euro (Haverkort et al, 2009). Over 20 R genes conferring race-specific (e.g., R1 and R2), intermediate spectrum (e.g., R2 and Rpi-blb3), or broad spectrum (e.g., Rpi-blb and Rpi-vnt1.1) resistance have been identified from several Solanum species, and large efforts have been taken to introduce broad-spectrum R genes into cultivated potato to achieve durable resistance to late blight (Haverkort et al, 2016). The underlying molecular mechanisms for the activation and execution of R gene-dependent resistance of potato is still largely unknown
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
