Benefits of a root fungal endophyte on physiological processes and growth of the vulnerable legume tree Prosopis chilensis(Fabaceae)

Aims Desertification is a major concern in arid and semi-arid regions globally.Understanding interactions between vulnerable plant spe-cies and associated microbial symbionts may have important appli-cations for conservation and restoration strategies in affected areas.Methods In this study,we evaluated the root-associated fungal endophyte community in Prosopis chilensis,a vulnerable and threatened arid-adapted tree of northern Chile.Host benefits in terms of physiologi-cal performance and plant growth were also assessed.Endophytic fungi were isolated from asymptomatic roots by the culture method for molecular identification of the 18S rRNA gene.The dominant fungal endophyte(Penicillium sp.)in the community was later used in inoculation experiments to assess its effect on maximum quan-tum efficiency of photosystem II(_(PSII)),(Fv/Fm)actual _(PSII) efficiency(Φ_(PSII)),and non-photochemical quenching(NPQ).Total sugars,starch content,malonaldehyde(MDA),nitrogen content(%)and growth traits were also measured.Important Findings WhereasΦ_(PSII) increased significantly in endophyte-inoculated plants,NPQ was found to decrease.No effect of endophyte inocula-tion on sugars and MDA was detected,but starch content,leaf nitro-gen content,number of leaves and shoot biomass were found to increase.Results revealed that inoculation of endophytic Penicillium fungal isolate can provide significant physiological benefits to the host plant P.chilensis.Its presence resulted in greater _(PSII) efficiency and higher leaf nitrogen and carbohydrate content,enhancing host plant growth.These findings highlight the importance of consider-ing the fungal endophyte community of this vulnerable species as an important tool to the design of further revegetation and conserva-tion programs.

Influence of microbial priming and seeding depth on germination and growth of native wildflowers

Background:Using native wildflowers for restoring marginal lands has gained considerable popularity.Establishment of wildflowers can be challenging due to several environmental factors.Restoring the microbial community in degraded habitats can potentially result in the native plant performance and habitat restoration.This study was conducted to investigate the impact of native soil microbes and seeding depth on germination of south Texas native wildflowers.Two wildflower species,Ratibida columnifera(Nutt.)(Mexican Hat)and Verbesina encelioides(Cav.)(cowpen daisy),were treated with microbial wash extracted from native soils,and germination rate was recorded for 14-day period.We further analyzed the growth,biomass allocation,and root colonization by mycorrhizal fungi in these two plants growing them in a plant growth chamber for 6 weeks.To determine the impact of seeding depth,we planted the seeds of the two plant species at 2-cm,6-cm,and 12-cm depth and monitored germination and plant growth.Results:The two species responded differently to the seeding depth and microbial wash treatments.Microbial wash treatment resulted in higher germination rate in R.columnifera compared to control,while it did not have any impact on V.encelioides seed germination.While microbial treatment did not influence the total biomass,it had a significant impact on the biomass allocation in both the plant species.R.columnifera seeds germinated at both 2-cm and 6-cm depth and did not germinate at 12 cm,while the V.encelioides seeds germinated only at 2 cm and did not germinate at 6-cm or 12-cm seeding depth.Conclusions:While our results are species specific,our results indicate that native soil microbes can potentially improve the seed germination and growth of wildflowers.Our results also indicate the importance of specific seeding depth when sowing wildflower seeds for habitat restoration.