Gene expression profiles in early leaf of rice(Oryza sativa)and foxtail millet(Setaria italica)

Plant anatomy is patterned early during leaf development which suggests studying the spatial–temporal transcriptomes of primordia will help identify critical regulative and functional genes.We successfully isolated the leaf primordia tissues from the C3grass rice and the C4grass foxtail millet by laser capture microdissection(LCM)and studied the gene expression throughout leaf developmental stages.Our data analysis uncovered the conserved expression patterns of certain gene clusters both in rice and foxtail millet during leaf development.We revealed genes and transcription factors involved in vein formation,stomatal development,and suberin accumulation.We identified 79 candidate genes associated with functional regulation of C4anatomy formation.Screening phenotype of the candidate genes revealed that knock-out of a putative polar auxin transport related gene NAL1 resulted significantly reduced veinal space in rice leaf.Our present work provides a foundation for future analyses of genes with novel functions in grasses and their role in leaf development,in particular the role in leaves with a contrasting C3vs.C4biosynthetic pathway.

Causal Association of Cardiac Function by Magnetic Resonance Imaging with Frailty Index:A Mendelian Randomization Study

Owing to the susceptibility of conventional observational studies to confounding factors and reverse causation,the causal association between cardiac function and frailty is unclear.We aimed to investigate whether cardiac function has causal effects on frailty.In this study,a two-sample Mendelian randomization(MR)study was conducted using genetic variants associated with cardiac function assessed by magnetic resonance imaging phenotypes as instrumental variables.Genetic variants asso-ciated with cardiac function by magnetic resonance imaging(including seven cardiac function phenotypes)and the frailty index(FI)were obtained from two large genome-wide association studies.MR estimates from each genetic instrument were combined using inverse variance weighted(IVW),weighted median,and MR‒Egger regression methods.We found that the increase in genetically determined stroke volume(beta-0.13,95%CI-0.16 to-0.10,p=1.39E-6),rather than other cardiac phenotypes,was associated with lower FI in MR analysis of IVW after Bonferroni correction.Sensitivity analyses examining potential bias caused by pleiotropy or reverse causality revealed similar findings(e.g.,intercept[SE],-0.008[0.011],p=0.47 by MR‒Egger intercept test).The leave-one-out analysis indicated that the association was not driven by single nucleotide polymorphisms.No evidence of heterogeneity was found among the genetic variants(e.g.,MR‒Egger:Q statistic=14.4,p=0.156).In conclusion,we provided evidence that improved cardiac function could contribute to reducing FI.These findings support the hypothesis that enhancing cardiac function could be an effective prevention strategy for frailty.