CRISPR-Cas systems endow the bacterial and archaeal species with adaptive immune mechanisms to fend off invading phages and foreign plasmids. The class 2 type VI CRISPR/Cas effector Cas13d has been harnessed to confer the protection against RNA viruses in diverse eukaryotic species. However a vast number of different viruses can potentially infect the same host plant resulting in mixed infection, thus necessitating the generation of crops with broad-spectrum resistance to multiple viruses. Here we report the repurposing of CRISPR/Cas13d coupled with an endogenous tRNA-processing system (polycistronic tRNA-gRNA, PTG) to target the multiple potato RNA viruses. Expression of Cas13d and four different gRNAs were observed in transgenic potato lines expressing the Cas13d/PTG construct. We show that the Cas13d/PTG transgenic plants exhibit resistance to either PVY, PVS, PVX or PLRV alone or two/three viruses simultaneously by reducing viral accumulation in plant cells. In sum, our findings provide an efficient strategy for engineering crops that can simultaneously resist infection by multiple RNA viruses.

Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas have been recognized as powerful genome-editing tools in diverse eukaryotic species, including plants, and thus hold great promise for engineering virus resistance in plants. Nevertheless, further attention is required regarding various issues associated with applying new powerful technologies in the field. This mini-review focuses on the recent advances in using CRISPR/Cas9 and CRISPR/Cas13 systems to combat DNA and RNA viruses in plants. We explored the utility of CRISPR/Cas for targeting the viral genome and editing host susceptibility genes in plants. We also provide insights into the limitations and challenges of using CRISPR/Cas for plant virus interference and propose individual combinatorial solutions. In conclusion, CRISPR/Cas technology has the potential to offer innovative and highly efficient approaches for controlling viruses in important crops in the near future.

The reniform nematodes of the genus Rotylenchulus infect over 300 species from numerous plant families in tropical, subtropical, and warm-temperate regions (Robinson et al. 1997; Redding et al. 2018). Rotylenchulus reniformis Linford & Oliveira, 1940 is the most economically significant species in the genus and parasitizes a wide variety of crops, such as cotton, soybean, several tropical fruit species, and vegetable crops including tomato (Robinson et al. 1997; Van Den Berg et al. 2016; Redding et al. 2018). Tomato is one of the most widely cultivated vegetables in China. In 2016 and 2017, a survey for plant-parasitic nematodes attacking tomato was performed in tomato fields near Huixian City, Henan Province in central China. Tomatoes were stunted and yields were reduced. Roots systems of sick plants were poorly developed. Soil and root samples were randomly collected from 30 locations, and the samples were taken from one 34-ha field. Soil samples were collected at a depth of 5 to 25 cm. Nematodes were i...

Pseudomonas fluorescens group, such as Pseudomonas protegens and Pseudomonas chlororaphis, can be utilized as insect-killing agents. Most insecticidal Pseudomonas described so far have high toxicity for insects of the order Lepidoptera. In this study, Pseudomonas strain PcR3-3 was isolated from the willow root. It showed a high mortality for the coleopteran species Plagiodera versicolora (Coleoptera: Chrysomelidae), but not for the lepidopteran Helicoverpa armigera. Strain PcR3-3 displayed high colonization ability in the P. versicolora compared with P. chlororaphis PCL1391, indicating that the insecticidal activities correlated with the colonization ability of Pseudomonas strain in the host. Phylogenetic analysis of the genome revealed that PcR3-3 belonged to P. chlororaphis subsp. aureofaciens. Numerous insecticidal protein-encoding genes, typical biosynthetic gene clusters for some insecticidal metabolite and type VI secretion system, known to be involved in insect pathogenicity, were present in the P. chlororaphis PcR3-3 genome. However, the insecticidal toxin Fit-encoding gene which commonly presents in P. chlororaphis, was not found in the P. chlororaphis PcR3-3 genome. Furthermore, there are some divergent insecticidal genes between P. chlororaphis PcR3-3 and P. chlororaphis PCL1391. This finding implies that P. chlororaphis PcR3-3 is a promising biocontrol agent for pest management applications. The P. chlororaphis–P. versicolora association can be used as a model system to study the interaction between Pseudomonas and coleopteran insects.