Improvement of glucosinolates by metabolic engineering in Brassica crops

Glucosinolates(GSLs)are a class of sulfur-and nitrogen-containing and amino acid-derived important secondary metabolites,which mainly present in plants of Brassicaceae family,including Brassica crops,such as broccoli,cabbage,and oilseed rape.The bioactive GSL meta bolites confer benefits to plant defense,human health,and the unique flavor of some Brassica crops.However,certain GSL profiles have adverse effects and are known as anti-nutritional factors.This has attracted mounting attempts to increase beneficial GSLs and reduce detrimental ones in the most commonly consumed Brassica crops.We provide a comprehensive overview of metabolic engineering applied in Brassica crops to achieve this purpose,including modulation of GSL biosynthesis,ablation of GSL hydrolysis,inhibition of GSL transport processes,and redirection of meta bolic flux to GSL.Moreover,advances in omics approaches,i.e,genomics,transcriptome,and metabolome,applied in the elucidation of GSL metabolism in Brassica crops,as well as promising and potential genome-editing technologies are also discussed.

Studies on the temporal,structural,and interacting features of the clubroot resistance gene Rcr1 using CRISPR/Cas9-based systems

Clubroot disease is a severe threat to Brassica crops globally,particularly in western Canada.Genetic resistance,achieved through pyramiding clubroot resistance(CR)genes with different modes of action,is the most important strategy for managing the disease.However,studies on the CR gene functions are quite limited.In this study,we have conducted investigations into the temporal,structural,and interacting features of a newly cloned CR gene,Rcr1,using CRISPR/Cas9 technology.For temporal functionality,we developed a novel CRISPR/Cas9-based binary vector,pHHIGR-Hsp18.2,to deliver Rcr1 into a susceptible canola line(DH12075)and observed that early expression of Rcr1 is critical for conferring resistance.For structural functionality,several independent mutations in specific domains of Rcr1 resulted in loss-offunction,highlighting their importance for CR phenotype.In the study of the interacting features of Rcr1,a cysteine protease gene and its homologous allele in canola were successfully disrupted via CRISPR/Cas9 as an interacting component with Rcr1 protein,resulting in the conversion from clubroot resistant to susceptible in plants carrying intact Rcr1.These results indicated an indispensable role of these two cysteine proteases in Rcr1-mediated resistance response.This study,the first of its kind,provides valuable insights into the functionality of Rcr1.Further,the new vector p HHIGR-Hsp18.2 demonstrated an inducible feature on the removal of add-on traits,which should be useful for functional genomics and other similar research in brassica crops.

WeiTsing: a new face of Ca^(2+)-permeable channels in plant immunity

Plants employ pattern-and effector-triggered immunity(PTI and ETI)to synergistically defend invading pathogens and insect herbivores.Both PTI and ETI can induce cytosolic Ca^(2+)spikes,despite in different spatiotemporal patterns,to activate downstream Ca^(2+)-dependent immune signaling cascades.While multiple families of Ca^(2+)-permeable channels at the plasma membrane have been uncovered,the counterparts responsible for Ca^(2+)release from intracellular stores remain poorly understood.In a groundbreaking paper published recently by Cell,the authors reported that WeiTsing,an Arabidopsis endoplasmic reticulum(ER)-resident protein that was specifically expressed in the pericycle upon Plasmodiophora brassicae(Pb)infection,could form resistosome-like Ca^(2+)-conducting channel and protect the stele of Brassica crops from Pb colonization.As the channel activity of WeiTsing was indispensable for its immune function,the findings highlight a previously underappreciated role of Ca^(2+)release from intracellular repertoire in promoting plant disease resistance.