BIOLOGIA PL~TAR]YM (PRAHA)

16 (1) : 76--77, 1974 I _ _ _

B R I E F CO]~d'MUN1CATION

Influence of Pigweed Mosaic Virus on Free Amino Acids o f P igweed (Amaranthus viridis L.)

SHAMSttER SINGH, V. S. VERMA, B . K . GOSWAMI a n d R . PADMA

Division of Mycology and Plant Pathology, Indian Agricultural Research Institute, 110012 :New I)elhl India

Accepted June 26, 1973

Abstract . An increase in the number of amino acids in Amaranthus viridis plants infected with pigweed mosaic virus was found.

Pigweed mosaic virus known to natural ly infect pigweed has been charac- terized by Sn~GH et al. (1972). Here an a t t empt is made to s tudy the dif- ferences between free amino acid contents of heal thy and virus infected pigweed plants.

Qualitative analysis was done by paper chromatography (BLocx et al. 1958). Standard amino acids (B.D.H. Chemicals Ltd. Peele, England) served as control. 10 g of fresh leaves from heal thy and infected plants of the same age were macerated with 80 % hot ethanol separately. The extract was thoroughly mixed with an equal volume of chloroform and centrifuged at 3 000 rpm for 15 rain. The upper layer free from pigments was evaporated to dryness on a water-bath. The dried material was dissolved in 2 ml. methanol and filtered. The filtrates were applied on Whatman No. 1 filter paper (28• cm) separately. A mixture of n-butanol: acetic a c i d : w a t e r in the ratio of 4 : 1 : 5 (V/V) was used as running solvent. Chromatograms were run in one dimension for 14 h. They were then dried and sprayed with 0.2% ninhydrin (indane-trione hydrate in n-butanol). Sprayed chromatograms were dried and heated in an oven at 80 ~ for 15 min. Chromatograms for all the 24 amino acids of the s tandard set were obtained using the same procedure. Charac- terization of the various amino acids was established by comparing the R f values of the chromatophores of the test materials with that of the s tandard set. The following table lists the observations made.

As the table indicates amino acids, alanine, cysteine, eystine, hydroxy- proline, nor-leucine, serine, tyrosine and valine were present only in the infected tissues and aspartic acid, dihydroxyphenyl-alanine and proline were

76

P I G W E E D MOSAIC VIRUS 77

encountered only in the healthy tissues while amino-n-butyric acid, arginine, glyeine, histidine, methionine and threonine were common to both. An increase in the amino acid composition of the infected plants may be due to the proteolysis of the host protein during pathogenesis or an increased

TABLE 1

EFFECT OF PIGWEED MOSAIC VIRUS on the free amino acids of Pigweed leaves

Detected

A B C Only in heal thy Only in diseased In both hea l thy and d:soased

t~ss ~e~ t issues t issues

Aspartie acid Dihyd :oxy-phonyl-alanine Proline

Atanlno Cysteino Cystine Nor-leucine Serine Tyrosine Valine

Amino-n-butyr ic acid Arginino Glycino Histidino Mothionino Throonino

metabolic rate always observed after infection (COMMO~E~ and NE~)~RI 1953, PO~TER 1959, GOODMA~ et al. 1967, GOSWAMI et al. 1971). On the other hand, absence of aspartic acid, dihydroxy-phenyl-alanine and proline in the dis- eased tissue may be attr ibuted to their utilization by the pathogen or de- gradation during enzymatic reactions.

Aeknowled9ement

The authors record their sincere grat i tude to Dr. S. P. 1%aychaudhuri, Head, Division of Mycology and Plant Pathology, Ind ian Agricultural 1%esearch Ins t i tu te , 1Wew Delhi, India, for facilities and constant encouragement.

References

BLOCK, 1%. J . , DvRRU~, E. L., ZWEm, G.: A Manual of Chromatography and :Paper Electro- phoresis. 2nd E4. - - P. 710. Academic Press, New York 1958.

COMMONER, B., NEHARI, V.: The effects of tobacco mosaic virus synthesis on the free amino acid and amide composition of the host. - - J. gen. Physiol. 36 : 791--805, 1953.

GOODMAN, 1%. N., KIRALY, Z., ZAITLIN, M.: The Biochemistry and Physiology of Infectious Plant Diseases. - - P. 354. D. Van Nost rand Co. Inc., London 1967.

GoswAr~I, B. K., 1%AYCHAUDHURI, S. P., NARIANL T. K.: Free Amino-Acid contents of the greening - - affected and hea l thy plants of sweet orange Citrus sinensis (L.) 0SBECK. - - Curr. Sci. 40 : 469--471, 1971.

PORTER, C. A.: Biochemistry of P lan t virus infection. - - Adv. Virus 1%es. 6 : 75--91, 1959. S m o ~ S~A~S~ER, V A R ~ ASUeA~, CHENULV, V. V., VER.~, V. S.: Pigweed mosaic virus. - -

Phytopa th . Z. 75 : 82--85, 1972.