Infection Sites of Pseudomonas cichorii into Head Leaf of Lettuce.

Abstract

Sections of middle head leaf of lettuce were stained with fluorescein isothiocyanate-conjug antibody against Pseudomonas cichorii, a causal agent of bacterial rot of lettuce, and were observe under a fluorescent microscope. Fluorescent antibody-labeled P. cichorii cells were observed in stomat of the sections, which did not contain browing symptom of the disease. Special fluorescent specks deriv from P. cichorii were most frequently observed in guard cells and intercellular spaces of substoma cavities. Browing, which was the initial symptom of disease, progressed from epidermis to mesophl In advance of progress of browing symptom, specific fluorescent specks were observed in intercellu spaces of epidermis and then were observed in intercellular spaces of mesophyll. These results sugge that P. cichorii first invaded head leaf of lettuce through stomata, later multiplied in intercellular space of epidermis and colonized intercellular spaces of mesophyll. Specific fluorescent specks were also observed in leaf hairs.

Bacterial rot of lettuce caused by Pseudomonas cichorii in Turkey

“…Numerous lesions enlarged and coalesced, causing moist, greenish or yellowish to black areas, but no soft rot was observed on the infected plants in advanced stages of the disease. These symptoms were consistent with those of bacterial rot described by Hikichi et al . (1996).…”

Implication of an Aldehyde Dehydrogenase Gene and a Phosphinothricin N-Acetyltransferase Gene in the Diversity of Pseudomonas cichorii Virulence

“…[ 6 ] demonstrated that P. cichorii strains acquired the hrp genes through horizontal transfer from a common ancestor with the S-PAI of P. viridiflava and implicated the hrp in its virulence. Symptoms on P. cichorii -infected lettuce leaves are characterized by shiny, dark brown, firm necrotic spots [ 2 , 3 ]. P. cichorii also causes necrotic spots on eggplant distinct from the disease symptoms on lettuce leaves [ 6 , 7 ].…”

“…Pseudomonas cichorii causes bacterial rot in lettuce, which is characterized by shiny, dark brown, firm necrotic spots on leaves underneath the second or the third outermost head-leaves [ 1 , 2 , 3 ]. P. cichorii reportedly causes midrib rot of greenhouse-grown butterhead lettuce [ 4 ].…”

Epidemiology of Pseudomonas cichorii, the Cause of Lettuce Midrib Rot

“…1977). The pathogen enters lettuce head leaves, in contact with outer leaves, through stomata, multiplies in intercellular spaces of epidermis and mesophyll and moves into the vascular bundle (Hikichi et al. 1996a,b, 1998).…”