Vigna Sinensis Endl Research Articles

Studies on indicator plants for citrus viruses. 1

1. Thirty two species of leguminous plants were inoculated with the sap from the young shoots of Satsuma orange showing symptoms of Satsuma dwarf. Nine species including cowpea (Vigna sinensis Endl.), asparagus bean (Vigna sesquipedalis Wight), kidney bean (Phaseolus vulgaris L.), Crotalaria spectabilis Roth, peanut (Arachis hypogaea L.), garden pea (Pisum sativum L.), Chinese milk vetch (Astragalus sinicus L.), sword bean (Canavalia gladiota DC.), and Japanese clover (Microlespedeza striata Makino) were proved to be susceptible to a virus present in the affetced trees. Two species of Chenopodiaceae and three species of Cucurbitaceae were not subject to it. The authors temporarily propose the name “Satsuma dwarf virus” to this legume infecting virus.2. Among the susceptible plants listed above, Blackeye cowpea and kidney bean (Satisfaction) showed the most characteristic symptoms. The former showed mottling and vein clearing on the leaves, and necrotic streaks on the petioles as well as on the stems. The latter also developed clear mottling and vein clearing on the foliage of most plants that were infected by sap-inoculation. These two species appear to be good indicator plants. However, retransmission from infected legume plants to Satsuma orange has not been successful in the tests so far conducted.3. Higher percentages of infection resulted when the expressed sap was buffered with about an equal volume of 0.05-0.1mol solution of K2HPO4.4. One-month old shoots of affected Satsuma orange were demonstrated to carry highly active virus in the leaves, bark and wood portions. One-year old shoots and relatively old current shoots carried active virus in the wood, but not in the bark of twigs or the leaves.

Virus infection and other factors affecting ribonuclease activity of plant leaves.

Abstract Rubbing of bean ( Phaseolus vulgaris L.) leaves, partial dehydration of cowpea [ Vigna sinensis (L.) Endl.] leaves, and inoculation of bean leaves with inactivated or viable pod mottle virus or of Datura stramonium L. leaves with tobacco mosaic virus resulted in increased ribonuclease activity of such leaves. The response after rubbing was more pronounced when the leaves were dusted with Carborundum prior to rubbing and when the medium contained Cu ++ or Zn ++ ions. The reaction was first noticeable approximately 2 hours after rubbing, reached its highest level 1 day after rubbing, and lasted for several days. Spraying of unwounded leaves with solutions of CuSO 4 also led to increased ribonuclease activity. Virus-infected leaves maintained higher levels of ribonuclease activity than healthy control leaves or leaves inoculated with inactivated virus. The effect of rubbing was not restricted to the upper epidermis, but extended into the mesophyll. Neither phosphatase nor phosphodiesterase activity significantly increased in bean or Datura leaves after rubbing of the leaves or after inoculation with virus. It is concluded that increased ribonuclease activity is not a specific response to virus infection, but occurs as a general shock reaction. In bean leaves with high ribonuclease activity, more lesions were produced and more pod mottle virus was synthesized than in leaves with lower ribonuclease activity. However, stimulation of ribonuclease activity by rubbing of bean leaves did not lead to increased pod mottle virus lesion formation or to stepped-up virus synthesis. The significance of these results is discussed with respect to a possible role of ribonuclease in the synthesis of viral nucleic acid.

Some variables affecting the use of cowpea as an assay host for cucumber mosaic virus.

A study was made of the factors affecting the production of local lesions by cucumber mosaic virus on cowpea (Vigna sinensis (L.) Endl. ex Hassk.).

A mosaic disease of cowpea (Vigna sinensis Endl.)

A mosaic disease of cowpea (Vigna sinensis Endl.), prevalent in the bean‐growing regions of China, is described.The characteristic symptoms of the disease are conspicuous mosaic patterns, deformation and distortion of leaves and stunting of the plant.The cowpea mosaic virus is transmitted by Aphis rumicis L., Macrosiphum pisi Kalt. and Aphis gossypii Glov. It is also transmitted by artificial juice inoculation. The virus is seed‐bome. It withstands ageing m vitro for 3 days at 220 C. Its inactivation temperature is approximately 62° C. its tolerance to dilution is about 1: 3000.Cowpea mosaic virus infects lima bean and Adzuki bean in addition to cowpea.The relation of this virus to cowpea mosaic virus described by McLean and asparagus‐bean mosaic virus described by Snyder is discussed.

The Fungus Causing Zonate Leafspot of Cowpea

A disease of cowpea (Vigna sinensis (L.) Endl.), which has been designated here as the zonate leafspot (FIG. 1, A-B), was much in evidence, particularly in the Southern States during the 1943 growing season. The disease has been known for many years as a minor trouble of cowpea and the causal organism has been called Amerosporium oeconomicum Ellis & Tracy. One finds, however, that the fungus causing this leafspot has septate conidia, hence it does not agree with the description given by Ellis and Tracy (9, p. 102), and should not be referred to the genus Amerosporium. Because this leafspot of cowpea is so striking, many collectors have referred their specimens to Amerosporium, however, probably without a microscopic examination of the causal fungus. Since the leafspot is common, apparently wherever cowpeas are grown, and since so many have either wrongly identified the causal fungus or left their specimens undetermined, as indicated by the number being sent in for identification, both the disease and the causal organism appear to warrant further study.

Nota sobre a molestia de virus do fumo denominada faixa das nervuras

The present paper deals with the virus disease of the tobacco plant recently described by Kramer & Silberschmidt (12) under the name faixa das nervuras (veinbanding). New host plants are added to the list of suscepts, as follows : Nicotiana repanda Willd., JV. angustifolia (*), N. Gossey Domin, N. Sanderae Hort. ex. W. Watson, N. glutinosa L., N. longiflora Cav., N. paniculata L., Lycopersicon esculentum Mill., L. pimpinellifolium Mill., and Cyphomandra betacea Sendt. Datura stramonium L., already studied by Kramer & Silberschmidt (12) and Nicotiana glauca Grah., Nicandra physaloides Gaertn., Solanum nodiflorum (**), S. nigrum L., Lactuca sativa L., Brassica oleracea L., Vigna sinensis Endl. var. Black., and Dolichos lablab L., var. purpurens were found not to be susceptible to the virus. (*) This species was received with this name from the Division of Tobacco and Plant Nutrition, U.S.D.A. (**) One plant of S. nodiflorum out of 22 which were inoculated gave symptoms of veinbanding. However as no backinoculation was made it can not be stated with certainty if it was truly affected by this virus. The symptomatology on tobacco described by the above mentioned authors agrees as a whole with which has been observed that is : clearing of the veins, chlorotic spotting and veinbanding. In addition it is stated that the white necrotic spotting found associated with the disease on certain tobacco varieties, v. g. Sumatra and Turkish must be attributed to the same virus. On potato plants of the varieties President and Green Mountain the virus causes local streak-like symptoms followed by chlorotic mottling of young leaves. Late symptoms take the form of leaf-drop streak. The virus of faixa das nervuras is easily transmissible through the sap giving practically 100% of success. The physical properties of the virus are : tolerance to dilution 1:10.000, thermal death point 54°C. and logevity in vitro 72 hours. No vector of the virus is known. The statement of Kramer & Silberschmidt (12) that the virus of faixa das nervuras belongs to the group of the potato virus Y is confirmed. A discussion is given about the position of the virus within the group. Our results do not permit to state that the virus is more related to the veinbanding virus as claimed by these authors. It is also pointed out that the differences found in the litterature between the Y and veinbanding viruses are slight, justifying in the maximum the separation of both, but as strains of the same virus.