Suppression of ETI by PTI priming to balance plant growth and defense through an MPK3/MPK6-WRKYs-PP2Cs module

Pattern-triggered immunity(PTI)and effector-triggered immunity(ETI)are required for host defense against pathogens.Although PTI and ETI are intimately connected,the underlying molecular mechanisms remain elusive.In this study,we demonstrate that flg22 priming attenuates Pseudomonas syringae pv.tomato DC3000(Pst)AvrRpt2-induced hypersensitive cell death,resistance,and biomass reduction in Arabidopsis.Mitogen-activated protein kinases(MAPKs)are key signaling regulators of PTI and ETI.The absence of MPK3 and MPK6 significantly reduces pre-PTI-mediated ETI suppression(PES).We found that MPK3/MPK6 interact with and phosphorylate the downstream transcription factor WRKY18,which regulates the expression of AP2C1 and PP2C5,two genes encoding protein phosphatases.Furthermore,we observed that the PTI-suppressed ETI-triggered cell death,MAPK activation,and growth retardation are significantly attenuated in wrky18/40/60 and ap2c1 pp2c5 mutants.Taken together,our results suggest that the MPK3/MPK6-WRKYs-PP2Cs module underlies PES and is essential for the maintenance of plant fitness during ETI.

Characterization of biochars from woody agricultural wastes and sorption behavior comparison of cadmium and atrazine

Woody agricultural wastes have created enormous pressure on the environment.In this study,mulberry and cinnamon woodchips were reclaimed and prepared for biochars through pyrolysis technique at four different temperatures.Physicochemical properties showed that mulberry biochar exhibited higher pH,CEC and ash content than cinnamon biochar at each temperature.All biochars were utilized as adsorbents to remove cadmium(Cd)and atrazine(AT)from water.The adsorption isotherms were found to be well fitted by Freundlich and Langmuir models.The maximum adsorption capacities were 5306.41 mg/kg for Cd adsorption and 538.89 mg/kg for AT adsorption,respectively.Moreover,the principal component analysis,XPS and FTIR analysis proved that precipitation with phosphate in biochars acted as the key property that governed the adsorption capacity of Cd,whereas the porosity demonstrated a significant impact on the adsorption capacity of AT.Partial least squares(PLS)model was considered to be more favorable for predicting AT adsorption than Cd adsorption.The results of the present paper will be helpful for selecting most effective biochars from locally available woody agricultural byproducts that are optimized for contaminants removal from environment.

Biochar and soil properties limit the phytoavailability of lead and cadmium by Brassica chinensis L.in contaminated soils

The current study investigated the effect of biochars derived from cinnamomum woodchip,garden waste and mulberry woodchip on soil phytoavailable lead(Pb),cadmium(Cd)pools,and their uptake by Chinese cabbage(Brassica chinensis L.).The biochars were produced at 450℃of pyrolysis temperature.The contaminated soils were collected from Yunfu(clas-sified as Udept),Jiyuan(Ustalf)and Shaoguan(Udult)cities in China at the depth of 0-20 cm and amended with biochars at the rate of 3%w/w.After mixing the soil with biochar for 14 days,the Chinese cabbage was planted in the amended soils.Then,it was harvested on the 48th day after sowing period.In Udult soil,Chinese cabbage died 18 days after sowing period in control and soils amended with cinnamomum and mulberry biochars.Although only plants grown with the garden waste biochar treatment survived in Udult soil,amendment of garden waste or mulberry biochars at 3%w/w(450℃)to Udult soil significantly increased(4.95-6.25)soil pH compared to other biochar treatments.In Udept and Ustalf soils,the application of garden waste and mulberry biochars significantly improved plant biomass compared to control,albeit it was dependent on both biochar and soil properties.Garden waste biochar significantly decreased soil Cd phytoavailable concentration by 26%in the Udult soil,while a decrease of soil Cd phytoavailable concentration by 16%and 9%was observed in Ustalf and Udept soils,respectively.The available phosphorus in biochar and soil pH were important factors controlling toxic metal phytouptake by the plant.Thus,the amendment of soil with biochar at 3%can effectively reduce the mobility of Cd and Pb in soil and plant uptake.However,biochar and soil properties should be well-known before being used for soil toxic metal immobilization.