Powdery mildew disease resistance and markerassisted screening at the Pm60 locus in wild diploid wheat Triticum urartu

Triticum urartu,a diploid wild wheat and progenitor of the A genome of bread wheat,is an important resource for resistance to powdery mildew fungus caused by Blumeria graminis f.sp.tritici(Bgt).In the present study we systematically characterized the interaction between the Bgt fungus and T.urartu at the microscopic level.We also tested 227 T.urartu accessions for reaction to Bgt isolate E09 and discovered previously uncategorized powdery mildew resistance in this collection.Pm60 is a CC-NB-LRR type powdery mildew resistance gene that has at least three functional alleles,Pm60,Pm60a,and Pm60b.A marker-assisted screen targeting the Pm60 locus identified a non-functional allele of Pm60a,designated as Pm60a′.A sequence comparison of Pm60a′and Pm60a revealed that they differed by 58 SNPs and one 3-nucleotide deletion.Based on the sequence variations two molecular markers were developed to differentiate the functional Pm60a allele from the non-functional Pm60a′.Our screen revealed the presence of a previously uncharacterized powdery mildew resistance in T.urartu and provides new insights into the Pm60 locus.We believe that the two molecular markers developed here and new T.urartu resistant accessions will facilitate further identification of novel powdery mildew resistance genes and benefit breeding for powdery mildew resistance.

Microcarriers promote the through interface movement of mouse trophoblast stem cells by regulating stiffness

Mechanical force is crucial in the whole process of embryonic development.However,the role of trophoblast mechanics during embryo implantation has rarely been studied.In this study,we constructed a model to explore the effect of stiffness changes in mouse trophoblast stem cells(mTSCs)on implantation:microcarrier was prepared by sodium alginate using a droplet microfluidics system,and mTSCs were attached to the microcarrier surface with laminin modifications,called T(micro).Compared with the spheroid,formed by the self-assembly of mTSCs(T(sph)),we could regulate the stiffness of the microcarrier,making the Young’s modulus of mTSCs(367.70±79.81 Pa)similar to that of the blastocyst trophoblast ectoderm(432.49±151.90 Pa).Moreover,T(micro)contributes to improve the adhesion rate,expansion area and invasion depth of mTSCs.Further,T(micro)was highly expressed in tissue migration-related genes due to the activation of the Rho-associated coiled-coil containing protein kinase(ROCK)pathway at relatively similar modulus of trophoblast.Overall,our study explores the embryo implantation process with a new perspective,and provides theoretical support for understanding the effect of mechanics on embryo implantation.

SnRK1 Phosphorylates and Destabilizes WRKY3 to Enhance Barley Immunity to Powdery Mildew

Plants recognize pathogens and activate immune responses,which usually involve massive transcriptional reprogramming.The evolutionarily conserved kinase,Sucrose non-fermenting-related kinase 1(SnRK1),functions as a metabolic regulator that is essential for plant growth and stress responses.Here,we identify barley SnRK1 and a WRKY3 transcription factor by screening a cDNA library.SnRK1 interacts with WRKY3 in yeast,as confirmed by pull-down and luciferase complementation assays.Förster resonance energy transfer combined with noninvasive fluorescence lifetime imaging analysis indicates that the interaction occurs in the barley nucleus.Transient expression and virus-induced gene silencing analyses indicate that WRKY3 acts as a repressor of disease resistance to the Bgh fungus.Barley plants overexpressing WRKY3 have enhanced fungal microcolony formation and sporulation.Phosphorylation assays show that SnRK1 phosphorylates WRKY3 mainly at Ser83 and Ser112 to destabilize the repressor,and WRKY3 non-phosphorylation-null mutants at these two sites are more stable than the wild-type protein.SnRK1-overexpressing barley plants display enhanced disease resistance to Bgh.Transient expression of SnRK1 reduces fungal haustorium formation in barley cells,which probably requires SnRK1 nuclear localization and kinase activity.Together,these findings suggest that SnRK1 is directly involved in plant immunity through phosphorylation and destabilization of the WRKY3 repressor,revealing a new regulatory mechanism of immune derepression in plants.