The control of hormogonia induction/suppression by the alteration of scmucilage signaling molecules in Cycas plant in an endosymbiotic cyanobacterium

Abstract

Abstract This study focuses on the role of mucilage signaling molecules secreted by the Cycad plant in the regulation of hormogonia induction/suppression in a novel endosymbiotic cyanobacterium (Cyanocohniella cycadae sp. nov.) isolated from the coralloid root of Cycas circinalis. Through a series of experiments using a combination of extraction, screening, acid-hydrolysis, derivatization, and GC-MS approaches, we sought to identify and characterize the mucilage signaling molecules secreted by Cycas circinalis and their role in the regulation of hormogonia induction/suppression in Cyanocohniella cycadae. Our results indicated that the mucilage components secreted in the coralloid root (CA) vary with the pre-coralloid root (PCA) of the same Cycas plant. Hence, we identified the presence of specific monosaccharides like arabinose (14.93 %), galactose (5.61 %), xylose (6.46 %), glucose (6.70 %), and altrose (4.41 %) in CA results in the suppression of hormogonia, whereas, glucose (29.86 %), fructose (18.86 %), talose (6.73 %), and lyxose (3.88 %) in PCA induces hormogonia development. Overall, this study provides new insight into the role of the alteration of mucilage signaling molecules. A shift between hexose and pentose in the pre-coralloid and coralloid root switches the induction and suppression of hormogonia in the cyanobacterium respectively. Further studies are needed to elucidate the mucilage biosynthetic pathways in the regulation of hormogonia induction/suppression in a variety of endosymbiotic cyanobacteria.