Abstract
The objective of this work is to investigate the relationship between endo-β-mannanase and leaf abscission, and response to wounding in soybean (Glycine max). An endo-β-mannanase gene GmMAN1 was cloned from the abscission zone in petiole explants, and was heterologously expressed in E. coli. Polyclonal antibodies were raised against the fusion protein. The increases in activity, isoform numbers, and amounts of transcripts and proteins of GmMAN1 were found not only in the abscission zone but also in the non-abscission zone during petiole abscission in the explants, but not in these two tissues during leaf abscission artificially induced by ethephon treatment in the intact plants. The changes in endo-β-mannanase expression patterns in these two tissues were probably induced by the inherent mechanical wounding during the preparation of explants. When soybean plants were wounded by removing half of the leaf blade of the first pair of true leaves, the transcripts and proteins of GmMAN1 were induced in the leaves and stem, leading to the increases in enzyme activity and isoform numbers in them. It is concluded that the soybean endo-β-mannanase GmMAN1 is not associated with leaf abscission, but might be involved in the response to wounding.
Highlights
Endo-b-mannanase (EC 3.2.1.78) hydrolyzes the b-1, 4-linkages in the backbone of mannans, one of plant cell wall hemicelluloses
Up to 36 h, the activity in both the abscission zone (AZ) and non-abscission zone (NZ) increased gradually, no petiole abscised during this time
Abscission is the process by which plant organs are shed, including leaves, flowers and fruits. It includes a complex of biochemical and molecular events, such as de-novo synthesis of cell wall hydrolases leading to the breakdown of cell wall, in only a few layers of cells of the petiole, i.e. the AZ tissues
Summary
Endo-b-mannanase (EC 3.2.1.78) hydrolyzes the b-1, 4-linkages in the backbone of mannans, one of plant cell wall hemicelluloses. This enzyme plays an important role in plant growth and developmental events in which cell wall degradation is involved. Loosening of the micropylar endosperm cell walls, a prerequisite for the completion of seed germination in tomato, Datura ferox and Arabidopsis thaliana is accompanied by an increase in endo-b-mannanase activity [1,2,3]. Organ abscission and response of plants to wounding are other growth and developmental events that involve cell wall breakdown [7,8,9,10]. It is of interest to know if endo-b-mannanase plays a role in organ abscission and response of plants to wounding
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
