Tkansgenic Burley and Flue-Cured Tobacco with Resistance to Four Necrotic Isolates of Potato Virus Y

and

Tobacco

with

Isolates

Y

Sudarsono, J.

S.

L.

Parry,

G.

M.

E.

A. S. A.

and A.

K.

Weissinger

First, fourth, sixth, and eighth authors: Department af Crop Science, Box 7620, and second, third, and seventh authors: Department of

Plant North Carolina State University, Raleigh 27695; and author: RJR Inc., Bowman Gray

Technical Center, Winston-Salem, NC 02.

Sudarsona was by a fellowship from University Center Sciences, Agriculture University, Raya

ajaran, Indonesia, through The Indonesian Second University Development Project. We thank for technical assistance.

Accepted for publication 19 1995.

ABSTRACT

Sudarsono, Young, B., S. L., C., Hellmann, G. M., S. and Weissinger, A. K. 1995. Trans-

genic and flue-curd tobacco with to four necrotic isolates of potato Y. Phytopathology 85:

Transgenic (cultivars KY 14, and and flue-

cured (cultivar tobacco with resistance to four necrotic isolates of

potato were These tobacco were

transformed with a chimeric gene designed to express coat protein

from the necrotic Chilean isolate of PVY. CP expression among plants was undetectable by immunosorbent assay and Western blot Transgenic plants that harbored one to five phosphotransferase

transgene loci were identified. the NPT and the PVY CP chimeric genes were linked within a common no was

found the number of NPT and CP Inoculation of 41 independent plants with PVY-Chilean identified

eight resistant plants, while inoculation of 30 transgenic K326 plants identified six resistant plants. of 17 transgenic

plants with PVY-Chilean six resistant plants, while inoculation of transgenic plants with PVY isolate resulted in nine resistant plants. Progeny derived from

but symptomless plants were also to the Chilean. Europe VAM isolates of WY, demonstrating sexual transmission of the transgenes that condition resistance. We discuss the ability of the PVY-Chilean CP gene to transgenic tobacco KY 14, and from by necrotic isolates of PVY. The flue- cud cultivar which a gene simul- taneously conferring resistance against nematode and suscep- tibility to PVY strain protected this when

with the PW-Chilean

protein gene-mediated resistance,

virus resistance.

Potato virus is the type member of the

genus within the the largest family of plant (21). Infection of

tobacco

L.) with PVY results in symptoms ranging from vein banding

and

mild mosaic to severe leaf necrosis and necrotic lesions on veins and depending upon the isolate and geno- type. PVY infection also reduces tobacco yields and quality Infection of tobacco with strains indigenous to the southeastern United States can result in yield reductions o f

to 100% (14).

The of highly PVY isolates bas

been reported in countries throughout the world

recently, a necrotic isolate that exhibits mild symptoms in potato but causes severe necrosis in tobacco

has been identified and

is

interfering with commerce in seed potatoes from Canada

(G.

Jr., personal

Control of PVY is and the most viable approaches are the deployment of PVY-resistant cultivars and the use cross-protection between PVY strains (1

Unfortunately, acceptable sources of P V Y resistance are rare in

plasm (6). Tobacco breeding line NC 744

Corresponding author: A. K.

address: AKMUR@UNITY.NCSU.EDU

The Society

carrying the va gene (16) derived Virgin A Mutante confers either resistance or

tolerance to strains

of

indigenous to the southeastern United

States. However, tobacco genotypes carrying the va gene in condition are hypersensitive to blue mold disease

some strains of such as B and (I overcome this gene. A specific strain of desig-

nated symptoms in tobacco genotypes

that a gene resistance to root-knot nematodes and mild symptoms in genotypes lacking this gene This reaction is unaffected by the gene. It has not been possible to break this negative correlation between and resistance,

so

the utility of the gene in areas where the

is present i s Therefore, identification of alternative sources of resistance in commercial tobacco is desired.

Virus resistance expression of the coat protein gene in transgenic plants, often referred to as pathogen-derived tance, is useful for developing PVY-resistant and flue-cud tobacco. expression

of

the CP gene in trans- genic plant strategy has been used to protect

sp. from such as tobacco mosaic virus tobacco etch and potato X as well as

Yet essentially no research has been performed to examine the

use

of this strategy against in commercial tobacco cultivars. This report describes the virus-resistance effects afforded by integrating the necrotic gene