Changes in Physiological and Biochemical Characteristics of Floral Organ Development in a Soybean Cytoplasmic-nuclear Male Sterile Line

[Objectives]This study was conducted to explore the mechanism of soybean cytoplasmic-nuclear male sterility.[Methods]With soybean cytoplasmic-nuclear male sterile line JLCMS9 A and its homotype maintainer line JLCMS9 B as experimental materials,the activity of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT),malondialdehyde(MDA)content,starch content,soluble protein content,soluble sugar content and free proline content in flower buds,alabastrums and mature flowers were determined,and the contents and changes of auxin(IAA),gibberellin(GA3),isopentenyl adenosine(iPA)and abscisic acid(ABA)at the three stages were analyzed.[Results]The activity of SOD and CAT and the contents of MDA and free proline in the sterile line at the flower bud stage were lower than those of the maintainer line,but the opposite was true at the alabastrum stage and the flowering stage,and their values were higher than those of the maintainer line;the POD activity of the sterile line was significantly lower than that of the maintainer line at the flower bud stage,and the opposite was true at the alabastrum stage and the flowering stage,and its values were higher than those of the maintainer line;and the starch content and soluble sugar content of sterile line 9 A showed an overall upward trend,and were significantly lower than those of the maintainer line 9 B at the alabastrum stage and the flowering stage.During the whole development process of floral organs,the content of IAA in sterile line 9 A showed a trend of first increasing and then decreasing,and the content of iPA increased gradually.The contents of hormones in the sterile line were lower than those in the maintainer line.The ratios of IAA/ABA,IAA/GA3,IAA/iPA and ABA/GA3 in the sterile line were significantly different from those in the maintainer line.It is inferred that the abnormal physiological characteristics of floral organ development are related to the cytoplasmic-nuclear male sterility of soybean.The alabastrum stage may be a critical period for the occurrence of abnormal physiological and biochemical indexes in the floral organs of soybean cytoplasmic-nuclear male sterile lines.[Conclusions]This study provides a theoretical basis for the breeding of fine sterile lines of soybean and the research on the mechanism of sterility.

LDL receptor-related protein 1 (LRP1),a novel target for opening the blood-labyrinth barrier(BLB)

Inner ear disorders are a cluster of diseases that cause hearing loss in more than 1.5 billion people worldwide.However,the presence of the blood-labyrinth barrier(BLB)on the surface of the inner ear capillaries greatly hinders the effectiveness of systemic drugs for prevention and intervention due to the low permeability,which restricts the entry of most drug compounds from the bloodstream into the inner ear tissue.Here,we report the finding of a novel receptor,low-density lipoprotein receptor-related protein 1(LRP1),that is expressed on the BLB,as a potential target for shuttling therapeutics across this barrier.As a proof-ofconcept,we developed an LRP1-binding peptide,IETP2,and covalently conjugated a series of model small-molecule compounds to it,including potential drugs and imaging agents.All compounds were successfully delivered into the inner ear and inner ear lymph,indicating that targeting the receptor LRP1 is a promising strategy to enhance the permeability of the BLB.The discovery of the receptor LRP1 will illuminate developing strategies for crossing the BLB and for improving systemic drug delivery for inner ear disorders.