acter ia ▁use ▁N od ▁factors , ▁the ▁fung i ▁use ▁a ▁set ▁of ▁mole cules ▁denomin ated ▁My c ▁factor . ▁These ▁fung al ▁products ▁can ▁be ▁recognized ▁by ▁different ▁plants ▁and ▁are ▁not ▁designed ▁to ▁be ▁plant - specific . ▁When ▁these ▁My c ▁factors ▁are ▁recognized ▁by ▁the ▁plant ' s ▁root , ▁they ▁stim ulate ▁the ▁expression ▁of ▁different ▁gen es ▁involved ▁in ▁the ▁init iation ▁of ▁the ▁sym bi otic ▁association . ▁However , ▁the ▁secret ion ▁of ▁the ▁My c ▁factor ▁by ▁the ▁fung i ▁occurs ▁only ▁after ▁being ▁previously ▁stim ulated ▁by ▁str ig ol act ones ▁from ▁the ▁plant , ▁demonstr ating ▁the ▁necessary ▁role ▁of ▁these ▁comp ound ▁for ▁both ▁recognition ▁( from ▁fung i ▁and ▁from ▁plant ). ▁Str ig ol act ones ▁also ▁have ▁been ▁reported ▁to ▁produces ▁other ▁changes ▁in ▁fung al ▁cells , ▁such ▁as ▁an ▁increase ▁in ▁the ▁concentration ▁of ▁int rac ell ular ▁calci um ▁and ▁an ▁increase ▁in ▁li po ch it ool is ac char ides ▁( L CO s ), ▁the ▁latter ▁has ▁been ▁proved ▁to ▁be ▁one ▁of ▁the ▁My c ▁factors ▁produced ▁by ▁the ▁fung i ▁for ▁its ▁recognition ▁by ▁the ▁plant . ▁ ▁One ▁of ▁the ▁main ▁roles ▁of ▁ar bus cular ▁fung i ▁contained ▁in ▁sym bi otic ▁association ▁with ▁plants , ▁is ▁to ▁provide ▁soil ▁nut ri ents ▁to ▁the ▁plants , ▁especially ▁ph osph ate . ▁Thus ▁when ▁the ▁ph osph ate ▁in ▁the ▁de ple tion ▁zone ▁gets