Enrichment of beneficial cucumber rhizosphere microbes mediated by organic acid secretion

Resistant cultivars have played important roles in controlling Fusarium wilt disease,but the roles of rhizosphere interactions among different levels of resistant cultivars are still unknown.Here,two phenotypes of cucumber,one resistant and one with increased susceptibility to Fusarium oxysporum f.sp.cucumerinum(Foc),were grown in the soil and hydroponically,and then 16S rRNA gene sequencing and nontargeted metabolomics techniques were used to investigate rhizosphere microflora and root exudate profiles.Relatively high microbial community evenness for the Foc-susceptible cultivar was detected,and the relative abundances of Comamonadaceae and Xanthomonadaceae were higher for the Foc-susceptible cultivar than for the other cultivar.FishTaco analysis revealed that specific functional traits,such as protein synthesis and secretion,bacterial chemotaxis,and small organic acid metabolism pathways,were significantly upregulated in the rhizobacterial community of the Foc-susceptible cultivar.A machinelearning approach in conjunction with FishTaco plus metabolic pathway analysis revealed that four organic acids(citric acid,pyruvate acid,succinic acid,and fumarate)were released at higher abundance by the Foc-susceptible cultivar compared with the resistant cultivar,which may be responsible for the recruitment of Comamonadaceae,a potential beneficial microbial group.Further validation demonstrated that Comamonadaceae can be“cultured”by these organic acids.Together,compared with the resistant cultivar,the susceptible cucumber tends to assemble beneficial microbes by secreting more organic acids.

A self-driving solution for resource-constrained autonomous vehicles in parked areas

Autonomous vehicles in industrial parks can provide intelligent,efficient,and environmentally friendly transportation services,making them crucial tools for solving internal transportation issues.Considering the characteristics of industrial park scenarios and limited resources,designing and implementing autonomous driving solutions for autonomous vehicles in these areas has become a research hotspot.This paper proposes an efficient autonomous driving solution based on path planning,target recognition,and driving decision-making as its core components.Detailed designs for path planning,lane positioning,driving decision-making,and anti-collision algorithms are presented.Performance analysis and experimental validation of the proposed solution demonstrate its effectiveness in meeting the autonomous driving needs within resource-constrained environments in industrial parks.This solution provides important references for enhancing the performance of autonomous vehicles in these areas.

Coupling of the chemical niche and microbiome in the rhizosphere:implications from watermelon grafting

Grafting is commonly used to overcome soilborne diseases. However, its effects on the rhizodeposits as well as the linkages between the rhizosphere chemical niche and microbiome remained unknown. In this paper,significant negative correlations between the bacterial alpha diversity and both the disease incidence(r = – 0.832,P = 0.005) and pathogen population(r = – 0.786, P = 0.012)were detected. Moreover, our results showed that the chemical diversity not only predicts bacterial alpha diversity but also can impact on overall microbial community structure(beta diversity) in the rhizosphere.Furthermore, some anti-fungal compounds including heptadecane and hexadecane were identified in the rhizosphere of grafted watermelon. We concluded that grafted watermelon can form a distinct rhizosphere chemical niche and thus recruit microbial communities with high diversity. Furthermore, the diverse bacteria and the antifungal compounds in the rhizosphere can potentially serve as biological and chemical barriers, respectively, to hinder pathogen invasion. These results not only lead us toward broadening the view of disease resistance mechanism of grafting, but also provide clues to control the microbial composition by manipulating the rhizosphere chemical niche.