The Ultrastructure Characteristics of Secretory Cavities Associated with the Secretory Products of <i>Ginkgo biloba</i>

The origin, development and ultrastructure of secretory cavities in leaf of Ginkgo biloba and its relation to the secretory products were studied by optical and electron microscope. The results indicated that the formation pattern of the secretory cavities was schizo-lysigenous in nature. First, some original central secretory cells in the center of secretory cavities expanded, dissolved then moved aside schizogeneously forming an intercellular space. Later the central and peripheral secretory cells continued to dissolve making the intercellular space larger. This process continued until the central secretory cells degenerated, autolyzed and separated off into cavities. It has been assumed that the secretory products in the secretory cavities of Ginkgo biloba were synthesized mainly in the plastids and the endoplasmic reticulum (ER). However it was our observation that the Mitochondrion, Golgi Body and Cytoplasm were also involved in the synthesis and translocation of the secretions. After synthesized in ER and plastids, the secretory products approached the plasmalemma and fused their membranes with the latter in the form of samll vesicles, and then was eliminated to the spaces between the plasmalemma and the wall. At last the secretory products percolated through the wall that faded into an even looser mesh of fibrillar material toward the cavity.

Pecan kinome:classification and expression analysis of all protein kinases in Carya illinoinensis

Protein kinases(PKs)are involved in plant growth and stress responses,and constitute one of the largest superfamilies due to numerous gene duplications.However,limited PKs have been functionally described in pecan,an economically important nut tree.Here,the comprehensive identification,annotation and classification of the entire pecan kinome are reported.A total of 967 PK genes were identified from the pecan genome,and further classified into 20 different groups and 121 subfamilies using the kinase domain sequences,which were verified by phylogenetic analysis.The receptor-like kinase(RLK)group contained 565 members,which constituted the largest group.Gene duplication contributed to the expansion of pecan kinome,169 segmental duplication events including 285 PK genes were found,and the Ka/Ks ratio revealed they experienced strong negative selection.The RNA-Seq data of PK genes in pecan were further analyzed at the subfamily level,and different PK subfamilies performed various expression patterns across pecan embryo development or drought treatment,suggesting PK genes in pecan are involved in embryo development and drought stress response.Taken together,this study provides insight into the classification,expansion,evolution,and expression of pecan PKs.Our findings regarding expansion,expression and co-expression analyses lay a good foundation for future research to understand the roles of pecan PKs,and more efficiently determine the key candidate genes.