Peach latent mosaic viroid variants inducing peach calico (extreme chlorosis) contain a characteristic insertion that is responsible for this symptomatology.

The involvement of Peach latent mosaic viroid (PLMVd) in an extensive chlorosis of peach known as calico (PC) has been advanced but ultimate proof is lacking. Sequencing of 16 full-length PLMVd cDNA clones of a PC isolate revealed two groups of variants. Nine had a size (336-338 nt) similar to that of typical PLMVd variants of nonsymptomatic and mosaic-inducing isolates, whereas the other 7 were longer (348-351 nt) due to an insertion of 12-13 nt.