Insulin regulates plant immunity and induces polyploids
Insulin, a 6 kDa peptide hormone, produced by beta cells of the
pancreatic islets is one of the main anabolic hormones of the body. It
is considered to regulate the metabolism of carbohydrates, fats and
protein. Decrease in insulin sensitivity causes metabolic disorders such
as type Ⅱ diabetes and metabolic syndrome (Yaribeygi, Farrokhi, Butler,
& Sahebkar, 2019).
There are insulin-like materials in several plants which play essential
role in multiple physiological processes. They have the same molecular
masses, immunological and bioactive properties with insulin, such as
bovine insulin which was reported to stimulate growth and DNA synthesis
in the radicles and the coleoptiles of the embryonic axis in 200 μU
ml-1 (Avila-Alejandre et al., 2013). Chemically,
insulin has a great potential to affect physiology in plant, such as
increases of root length and weight in barley (Csaba, & Katalin, 1982).
It was reported that insulin (10−8 M) enhanced the
increase of root in lengths and weights significantly, and had a
similarly strong influence on the increase of coleoptile (Oliveira et
al., 2004). Qualitative cytological studies even indicated that insulin
may induce a polyploidism, associated with the Feulgen-positive bodies
in the cytoplasm (Csaba, & Katalin, 1982). Moreover, the regulation of
the cell-cycle restart by bovine insulin is demonstrated in germinating
embryonic axes (Avila-Alejandre et al., 2013). This suggests that plant
cells also have potential receptors to which hormones of vertebrates
could bind (Csaba, & Katalin, 1982). Molecular mechanism of insulin
would be worthwhile avenues to explore.