Cloning and expression of pathogenesis-related protein 4 from jelly fig (Ficus awkeotsang Makino) achenes associated with ribonuclease, chitinase and anti-fungal activities

The pathogenesis-related protein PR-4b from Theobroma cacao presents RNase activity, Ca2+ and Mg2+ dependent-DNase activity and antifungal action on Moniliophthora perniciosa

“…However, some exceptions were reported, for example, the CcPR-4 seemed to have a RNase activity mechanism different from those of the type A, B and C RNases [35]. Moreover, for class I PR-4 s, as FaPR4, the presence of the chitin-binding domain may contribute to the thermal stability of the protein avoiding the lack of RNase activity when the protein was submitted to heating [33]. …”

“…In the case of the PR-4 family, the presence or absence of chitin-binding domain is not correlated with the antifungal action; class I [32,33,37] as well as class II [26,29,38,39] PR-4 proteins presented antifungal activity (Table  1). Moreover, the presence of this domain is not associated to the chitinolytic function of the PR-4 proteins (Table  1) as observed in the case of AtHEL [32] and FaPR-4C [33]. The FaPR-4C protein, a truncated form of a class I protein obtained to mimic a class II PR-4, presented the same chitinases, RNase and antifungal activity as the original non truncated FaPR-4 [33].…”

“…Moreover, most of the PR-4 proteins have a signal peptide and some of them show transmembrane structure in the N-terminal region [28-30]. Some PR-4 proteins also present a C-terminal extension domain involved in protein targeting to the vacuole [31-33]. It has been shown that the barley Barwin protein is able to slightly interact with the oligosaccharide β-(1,4) tetramer of N-acetylglucosamine, an analog of chitin [27,34].…”

“…The class I tobacco PR-4 protein NtCBP20 showed antifungal activity against Trichoderma viride and Fusarium solani by causing germinative tube lyses and fungal growth inhibition [37]. In fig, the class I FaPR-4 protein as well as its truncated form FaPR-4c – lacking the N-terminal region to mimic a class II PR-4 – showed RNase, chitinase and antifungal activity [33]. However, some PR-4 only present RNase and antifungal activities [26,32,38] or RNase and DNase activity but no chitinase property [35].…”

Cloning and expression of class I chitinases in Hami melon after Penicillium infection

“…Of these, class I chitinases are only found in plants and have a structure consisting of an N-terminal signal peptide domain, CBD and catalytic domain (Lu et al, 2012). Class I chitinases can be further divided into basic class Ia and acidic class Ib.…”