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JOURNAL OF CULTURE COLLECTIONS

Volume 5, 2006-2007, pp. 90-93

 

 

 

EFFECT OF ALFALF= A MOSAIC VIRUS (AMV) ON THE CONTENT
OF SOME MACRO- AND MICRONUTRIENTS IN ALFALFA

 

Nejla Yardı= mcı1*, Handan Eryiğit1 and İbrahim Erdal2

 

1Süleyman De= mirel University, Faculty of Agriculture, Plant Protection Department, 32260, Çünür, Isparta, Turkey;
2Süleyman Demirel University, Faculty of Agriculture, Soil Science Department, 32260, Çünür, Isparta, Turkey

*Corresponding author, e-mail: nejyard@zira= at.sdu.edu.tr

 

 

Summary=

Leaves showing mosaic virus symptoms were collected for analyses from alfalfa growing areas in the Isparta region. Alfalfa mosa= ic virus (AMV) was detected in the plant samples by using mechanical inoculati= on of test plants and serological tests. The macro- and microelements were ass= ayed in the infected plant samples in order to determine the effects of AMV on t= he nutrient content of alfalfa. The quantity of P, Fe, Cu, Zn and Mn decreased= and N increased in the infected alfalfa leaves as compared to the healthy plant samples, while K did not change. The forage containing virus infected alfal= fa could not be harmful for the domestic animals, and the nutritious value is = even improved because of the increased protein contents.

 

Key words: alfalfa mosaic virus, alfalfa, nutrient contents.

 

 

Introduction

Alfa= lfa (Medicago sativa, Fabaceae) is a very important forage legume having high nutrient value as compared to other plants. Protein content of alfalfa is about 35 %= . Alfalfa fixes air free nitrogen into the soil, providing a potential source of natu= ral fertilization for plants [4].

Alfa= lfa is rich in protein, mineral elements, trace elements and vitamins, and it is m= ore valuable as a forage grass compared to the rest of the legumes, the Poaceae grasses and forage plants = of other families. The optimum nutrient contents of M. sativa are shown in Table 2 [10].

Some= plant diseases, pests, parasites and weeds affect the production of alfalfa. A significant part of the most common alfalfa diseases is comprised of viral infections. Alfalfa has been reported to be attacked by more than 28 plant viruses [7].

Alfa= lfa mosaic virus (AMV) is one of the most important and wide spread plant virus= es, and it is found to infect 599 species belonging to 245 genera of 68 familie= s, most of which are of the Fabaceae <= /i>family. AMV can be transferred from infected to healthy alfalfa plants in various w= ays: through mechanical inoculation by plant sap, by seeds, by aphids in a non-persistent manner, by dodder (C= uscuta), and by weed seeds [7, 9, 13]. The typical symptoms of AMV infecti= on of alfalfa are bright green and yellow plant color, chlorotic mottle between the lateral veins of leaves, vein banding, and leaf and petiole distortion. Additionally, root necrosis and plant death may appear in susceptible varieties. Severe stunting and dwarfing occur in alfalfa plants infected wi= th AMV. Deformation, curling, chlorotic banding and mosaic are also seen in ea= rly growing leaves [17].

AMV infection in alfalfa fields reduces fodder yield by 14.8 to 22.8 % and= by 15 to 18.1 % on a fresh and on a dry weight basis, respectively. In the field, AMV infection rates appear between 53 and 76 %, and the yield losses comprise 11 to 17 %, respectively. The amount of fresh grass decreases significantly with AMV [3]. In Czechoslovakia, the death rat= e of plants infected with AMV ranges between 26.6 and 80 % depending on gro= wing areas [11]. The virus also impedes the growth of alfalfa and reduces re-shooting rate after cutting [12].

Many researchers report physiological and biochemical disorders due to pathologic changes in plants. Protein content of bean leaves grows up with Pseudomonas syringae infection. Respiration rate increases in bean plants with bean common mosaic virus dis= ease on the 9th and the 15th day after inoculation. The le= aves of cotyledon plants infected by cucumber specific mosaic virus cause high chlorophyllase enzyme activities and chlorophyll demolition [14]. Another research on the same virus reports that the sugar content decreases, but fr= ee amino acids increase and protein level is considerably high in the infected cucumber leaves [1, 8]. Watermelon mosaic virus infection increases the protein content, but depresses other physiological and biochemical activiti= es such as respiration rate, and reduces starch, sugars and total nitrogen contents in diseased compared = with healthy plants [8]. Green part, seed and nitrogen fixation decrease with vi= ral infection. Occurrences of nodules on the plant roots are reduced by AMV infections [7, 15].

The = aim of this research was to determine the effects of AMV on the nutrient content of alfalfa plants.

 

Materials and Me= thods=

Leaf= samples from alfalfa plants exhibiting AMV-like symptoms were collected in the Ispa= rta region. The alfalfa leaves were kept frozen at –20 oC= in sterile polyethylene bags.

Alfalfa samples were tested for presence of the virus by an AMV spec= ific ELISA detection kit (Agdia Company, Elkhart, USA) usin= g the previously reported DAS-ELISA method [6]. Absorbance values were measured at 405 nm with a microplate reader (EL X 800 Universal Microplate Reader, Bio-Tek Instruments, Inc. B-2610 Wilrijk, Belgium).=

Inoculums from AMV infected alfalfa leaves were prepared in phosphate buffer (0.01 M, pH 7.2, 1 ml per 1 g of leaf material) and were applied to= test plants. The inoculated test plants were grown in greenhouse conditions at 1= 8‑20 oC until the disease symptoms were observed [9]. No application was done to the control plants.

Alfa= lfa leaves (young and elder, mix) with viral symptoms were used for analyses. T= he samples were washed in tap water to remove surface residues and soaked in 0.2 N HCl for 20 s. Following 4 or 5 rinses with distilled water, samples were dried at 65 oC for 48 h to a constant weight. Dried samples were ground by using a mortar and pestle, and were stored in polyethylene bottles.

Nitrogen content in samples was deter-min= ed according to the Kjeldahl method [5]. For this purpose, 0.5 g of the ground s= ample were digested using a block digesting system (KB 8 S Kjeldatherm, Gerhardt)= in digesting tube with 6 ml of concentrated H2SO4 in the presence of 5&nbs= p;g of a catalyst (K2SO4 + CuSO4). A= fter 40 % NaOH (w/w) was added, the sample was distilled using an automated unit (VAP20, Gerhardt). The ammonium N was fixed in 2 % H3B= O3 and was titrated with 0.1 N H2SO4 in the presenc= e of an indicator (bromocresol green and methyl red in 95 % ethanol). The N content was calculated according to the following equation:

 

N (%) =3D=

(ml= H2SO4 for sample titration - ml H2SO4 for blank titration) x Normality of H2SO4 x 1.4

sam= ple dry weight in grams

 

The protein content in the plant was determined = by multiplying the N amount by 6.25 factor [5].

For determining the P, K, Fe, Cu, Zn and Mn content in plant tissues, 0.5 g samples were dry-ashed at 500 ± 50 oC for 6 h. The residue was dissolved in 5 ml of 4 N HNO3, filtrated and was then filled up to 100 ml with distilled water. Phosphorus content in the filtrate was determined with a spectrophotometer = at 430 nm according to the vanadomolybdophosphoric acid yellow color meth= od. The other elements were measured by an atomic absorption spectrophotometer [16].

 

Results and Discussion

AMV = infection in the plant samples of diseased alfalfa was proved by DAS-ELISA. The react= ion of the test plants is presented in Table 1. All the AMV infected sampl= es induced similar symptoms. Chenopodi= um amaranticolor and Ch. quinoa displayed local lesions. On the other hand, Nicotiana tabacum cvs Samsun NN, White Burley and Xanthii, and N. glutinosa showed systemic infection as well as local reaction [9].

 

Table= 1. Symptoms of test plants induced after inoculation with AMV infected alfalfa samples.

Test plants

Symptoms

= Ch. amaranticolor

= Necrotic local lesions

= Ch. quinoa

= Necrotic local lesions

= Dat= ura stramonium

= Necrotic local lesions, deformation=

= N. tabacum cv. Xanthii

= Systemic mosaic, deformation, necrotic and chlorotic local lesions

= N. tabacum cv. Samsun NN

= Systemic mosaic, deformation, chlorotic local lesions

= N. tabacum cv. White Burley

= Systemic mosaic, deformation, chlorotic local lesions

= N. rustica

= Systemic mosaic, deformation, necrotic local lesions

= N. glutinosa

= Systemic mosaic, deformation, chlorotic local lesions

= Gom= phrena globosa

No symptoms

 

The = alfalfa samples in which the AMV infection was detected by serological test and by mechanical inoculation of indicator plants were used in the next study.

The quantities of N, P,= K, Fe, Zn, Mn and Cu in the infected and healthy control alfalfa samples are presented in Table 2. The protein content was 35.31 % in healthy plants and 37.25 % in AMV infected plants, respectively.

 

Table= 2. Changes of some macro- and micronutrients in infected with AMV and healthy alfalfa plants.

Nutrients=

Infected plants

Healthy plants

Optimum ranges= of nutrients

N (%)

5.96

5.65

4.50 ‑ 5= .00

P (%)

0.31

0.40

0.26 ‑ 0= .70

K (%)

2.70

2.68

2.00 ‑ 3= .50

Fe (ppm)<= /o:p>

15.0

60.0

30 ‑ 250=

Cu (ppm)<= /o:p>

23.50

48.50

7 - 30

Zn (ppm)<= /o:p>

15.0

40.0

21 ‑ 70<= o:p>

Mn (ppm)<= /o:p>

25.0

35.0

31 ‑ 100=

 

The obtained data showed that the con-tents of Fe, Cu, Zn and Mn in leaves markedly decreased with A= MV infection, whereas the amount of N slightly increased. No significant chang= es were observed in leave K content. These results could be due to the possible adverse effects and alterations in plant metabolism and cell integrity indu= ced by viral infections.

N, P and K are mobile elements in plants, and they are actively transported to the young tissues = when needed. The disease resistance and plant growth can adversely be affected b= y P deficiencies. Fe is a less mobile element; young growing leaves in particul= ar are more susceptible to Fe deficiencies. Cu, Zn and Mn are immobile element= s in the plant tissues. Zn and Mn directly constitute chlorophyll. Cu is also reported to increase the chlorophyll formation [16].

In previous studies, the virus infected plants were reported to contain more N than control plants by analytic calculations. Agrios [2] ob-served in the diseased plants that the= ir own protein level decreased, but the virus specific protein increased. Consequently, the established higher total protein content was more likely = to be due to the increased level of viral proteins in the plant.

In conclusion, the presented investigation demonstrated that AMV infected alfalfa ac-cumulated= lower amounts of heavy metals. Hence, the forage containing virus infected alfalfa could not be harmful for the domestic animals. At the same time, the nutrit= ious value is not decreased and is even improved because of the increased protein contents.

 

References

1.  Adzhemyan, L. A.= , Z. G. Gevorkyan, V. A. Amirkhanyan, 1976. Biologicheskij Zhurnal Armenii, 29 (1), 9= 1‑94.

2.  Agrios, N. G., 1= 997. Plant Pathology, San Die-go, London, Boston: Academic Press.

3.  Bailis, K.W., L.= A. A. Ollennu, 1986. Plant Pathology,= 35, 162‑168.

4.  Bergman, W., 199= 2. Visual and Analytical Diagnosis, <= st1:City w:st=3D"on">Jena, S= tuttgard, New York: Fisher.

5.  Bremler, J. M., = 1965. Methods of Soil Analysis, Madison: American= Society of Agronomy Inc.

6.  Clark, M. F., A. N. Adams, 1= 977. J. Gen. Virol., 34, 475-483.

7.&n= bsp; Edwardson, J. R., R. G. Christie, 1986. = Fla. Agric. Exp. Stn. Monogr., = 14, 30.

8.  Erdiller, G., F. Ertunç, 1987. J. Turk. Phyto= pathol., 16 (3), 105‑118.

9.  Jaspars, E. M. J= ., L. Bos, 1980. CMI/AAB Descriptions of = Plant Viruses, No. 229.

10.  Jones, J. B., B.= Wolf, H. A. Mills, 1991. Plant Analysis Handbook, Athens (GA), USA: Micro-Macro Publishing Inc.

11.  Jurik, M., 1987.= Rev. Plant Pathol., 63 (7), 276.

12.  Miczinski, K. A.= , C. Hiruki, 1988. Rev. Plant Pathol., 67 (3), 144.

13.  Nienhaus, F. 198= 1. Virus and Similar Diseases in Tropical and Subtropical Areas<= /i>, German Agency= for Technical Cooperation (GTZ), 221.

14.  Sing, R., R. B. = Singh, R. D. Srivastava, 1977. Ind. J. Exp. Biol., 15 (1), 82‑83

15.  Tu, J. C., T. M.= Holmes, 1980. Phytopathology, 97, 1-9.

16.  Walinga, I., W. Van Vark, V. J. G. Houba, J. J. Van der Lee,= 1989. Soil and Plant Analysis, Wageningen, The Neth= erlands: Wageningen Agricultural University.

17.  Yardımc= 5;, N., S. Açıkgöz, 1997. J. Turk. Phytopathol., 26 (1), 23‑30.

 

 

 

ЕФЕКТ НА ЛЮЦЕРНОВОМi= 4;ЗАИЧНИЯ ВИРУС (AMV) ВЪРХi= 9; СЪДЪРЖАНИЕi= 8;О НА НЯКОИ МАКРО- И МИКРОЕЛЕМЕi= 3;ТИ ПРИ ЛЮЦЕРНАТА<= /span>

 

Нежла Ярдъмджъ1*, Хандан Ерии = 90;1, Ибрахим Ердал2

 

= Резюме

&= #1054;т люцернови площи в района на Испарта са с= 098;брани и анализиранl= 0; листа с мозаични ви = 88;усни симптоми. В растителниm= 0;е проби е откр= 080;т люцерновомl= 6;заичния вирус (AMV) чрез прилагане н = 72; механично инокулиранk= 7; на индикаторнl= 0; растения и серологичнl= 0; тестове. В заразените листа са изследвани = 84;акро- и микроелемеl= 5;тите, за да се определи еф = 77;ктът на AMV върху хранителниn= 3; състав на лю= 094;ерната. Количествоm= 0;о на P, Fe, Cu, Zn и Mn намалява, а на N се увеличава в сравнение с = 98;с здрави люцернови листа. Съдържаниеm= 0;о на K не се променя. Фуражът, съдържащ вирусно бол = 85;а люцерна ням = 72; да е вреден за селскостопk= 2;нските животни, а хранителнаm= 0;а му стойност дори нараства, поради увеличенотl= 6; белтъчно съдържание.

 

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