Planta (BEE.) 86, 195--196 (1969)
Short Communication
Abscisic Acid in Penicillium italicum R. RUDNICKI, I-I. BORECKA a n d J. PIENI4ZEK l~esearch Institute of Pomology, Skierniewice, Poland ]~eceived March 10, 1969
Summary. Abscisic acid (ABA) was found in Penicillium italicum Wehmer collected from the surface of infected oranges. After growth and subculturing 6 times on Czapek's medium, the fungus did not contain any detectable ABA. Abscisie acid (ABA) has been f o u n d in m a n y species of higher p l a n t s (MIL]~Om~OW, 1967) b u t no d a t a are yet available on its presence i n lower plants. I t has been previously reported (BoxECKA a n d PIENIAiEK, 1968) t h a t both n a t u r a l A B A extracted from pears, apples a n d strawberries, a n d s y n t h e t i c A B A s t i m u l a t e d the g e r m i n a t i o n of pathogenic fungi such as Gloeosporium album Osterw. a n d Botrytis cinerea Pers. Penicillium italicum, a pathogenic fungus of citrus fruits, was chosen for s t u d y i n preference to other species because it was available i n sufficient q u a n t i ties from r o t t i n g oranges. I t is k n o w n t h a t citrus fruits c o n t a i n A B A (MiLBOl~aOW, 1967). The fungus was collected from the surface of infected oranges (mixture of varieties) from a commercial store, and was identified as Penicillium italicum Wehmer (RAPER and THO•, 1949). About 30 g fresh weight was used for the extraction of ABA. The fungus was also inoculated on Czapek's medium and about 20 g of fungus (aerial hyphae, condidiophores with spores) obtained after the 6th consecutive inoculation were also extracted for ABA. The fungal material was homogenized in 0.25 1 of 80% ethanol and filtered. The alcohol was evaporated under vacuum at 50~. The methods for extraction, purification and bioassay were as previously described (RUDNICKI, 1969). Both paper chromatography (Whatman No. 3) and thin-layer plates (Silica gel GF-254, Merck) were employed. Racemic synthetic ABA (Shell) was used as a chromatographic marker. The concentration of ABA in the fungus was calculated from bioassays and from spectrophotometrie determinations using a Zeiss VSU-1 spectrophotometer. P. italicum collected from the surface of infected oranges contained a b o u t 1.33 izg of the cis-trans a n d 0.94 ~g of the t r a n s - t r a n s isomer of ( + ) - A B A per gram fresh weight. The identification was based on the Rf values i n 4 solvent systems using s y n t h e t i c A B A as marker, on the fluorescence test with sulphuric acid, on the U V - a b s o r p t i o n spectrum, a n d on biological a c t i v i t y i n the wheat-coleoptile straight-growth test (see RUD~IOKI, 1969).
196
R. RUI)NICKIet al. : Abseisic Acid in Penlcillium italicum
I n the fungus cultured on Czapek's medium no inhibitory activity was detected when the purified extract was examined for A B A using the wheat-coleoptile straight-growth test, nor did a n y of the other techniques described above indicate the presence of ABA. MXLBO~OW (1967) found t h a t lemon skin contained 0.097 mg/kg A B A but no information is available on the concentration of A B A in oranges. Our results indicate t h a t A B A is found only in P. italicum collected directly from the surface of infected oranges. I t is therefore likely t h a t the fungus takes up A B A from its host. The absence of A B A in P. italicum after 3 m o n t h s ' growth, with 6 consective transfers, on Czapek's m e d i u m raises a question as to whether A B A is an endogenous p r o d u c t of this fungus, and w h a t role it m a y play in the spread of the infection on the fruit. P. italicum is k n o w n to remain viable for only a short time (less t h a n a year) when ~way from its host (RAPE~ and THOM, 1949). I t seems therefore possible t h a t A B A absorbed b y the fungus from the fruit influences its viability. W o r k is in progress to elucidate these problems. References :BOlgECKA,H., and J. PIENI)~ZEK: Stimulatory effect of abscisic acid on spore germination of Gloeosporium album Osterw. and Botrytis eincrea Pers. Bull. Acad. pol. Sci., C1. V, 16, 657--661 (1968). MILBOR~ow, B.V.: The identification and measurements of (+)-abscisinII [(+)-Dormin] in plants. Planta (Berl.) 76, 93--113 (1967). RAPER, K. :B., and CH. T~o~: A manual of the Penicillia. Baltimore: Williams & Wilkins 1949. Ru~)NIcKI, R. : Studies on abscisic acid in dpple seeds. Planta (Berl.) 86 63--68 (1969). }~. RUDNICKI, H. BO~ECKA,J. PIENI4~I~K Research Institute of Pomology ul. Pomologiczna 22 Skierniewice, Poland
Short Communication
Abscisic Acid in Penicillium italicum R. RUDNICKI, I-I. BORECKA a n d J. PIENI4ZEK l~esearch Institute of Pomology, Skierniewice, Poland ]~eceived March 10, 1969
Summary. Abscisic acid (ABA) was found in Penicillium italicum Wehmer collected from the surface of infected oranges. After growth and subculturing 6 times on Czapek's medium, the fungus did not contain any detectable ABA. Abscisie acid (ABA) has been f o u n d in m a n y species of higher p l a n t s (MIL]~Om~OW, 1967) b u t no d a t a are yet available on its presence i n lower plants. I t has been previously reported (BoxECKA a n d PIENIAiEK, 1968) t h a t both n a t u r a l A B A extracted from pears, apples a n d strawberries, a n d s y n t h e t i c A B A s t i m u l a t e d the g e r m i n a t i o n of pathogenic fungi such as Gloeosporium album Osterw. a n d Botrytis cinerea Pers. Penicillium italicum, a pathogenic fungus of citrus fruits, was chosen for s t u d y i n preference to other species because it was available i n sufficient q u a n t i ties from r o t t i n g oranges. I t is k n o w n t h a t citrus fruits c o n t a i n A B A (MiLBOl~aOW, 1967). The fungus was collected from the surface of infected oranges (mixture of varieties) from a commercial store, and was identified as Penicillium italicum Wehmer (RAPER and THO•, 1949). About 30 g fresh weight was used for the extraction of ABA. The fungus was also inoculated on Czapek's medium and about 20 g of fungus (aerial hyphae, condidiophores with spores) obtained after the 6th consecutive inoculation were also extracted for ABA. The fungal material was homogenized in 0.25 1 of 80% ethanol and filtered. The alcohol was evaporated under vacuum at 50~. The methods for extraction, purification and bioassay were as previously described (RUDNICKI, 1969). Both paper chromatography (Whatman No. 3) and thin-layer plates (Silica gel GF-254, Merck) were employed. Racemic synthetic ABA (Shell) was used as a chromatographic marker. The concentration of ABA in the fungus was calculated from bioassays and from spectrophotometrie determinations using a Zeiss VSU-1 spectrophotometer. P. italicum collected from the surface of infected oranges contained a b o u t 1.33 izg of the cis-trans a n d 0.94 ~g of the t r a n s - t r a n s isomer of ( + ) - A B A per gram fresh weight. The identification was based on the Rf values i n 4 solvent systems using s y n t h e t i c A B A as marker, on the fluorescence test with sulphuric acid, on the U V - a b s o r p t i o n spectrum, a n d on biological a c t i v i t y i n the wheat-coleoptile straight-growth test (see RUD~IOKI, 1969).
196
R. RUI)NICKIet al. : Abseisic Acid in Penlcillium italicum
I n the fungus cultured on Czapek's medium no inhibitory activity was detected when the purified extract was examined for A B A using the wheat-coleoptile straight-growth test, nor did a n y of the other techniques described above indicate the presence of ABA. MXLBO~OW (1967) found t h a t lemon skin contained 0.097 mg/kg A B A but no information is available on the concentration of A B A in oranges. Our results indicate t h a t A B A is found only in P. italicum collected directly from the surface of infected oranges. I t is therefore likely t h a t the fungus takes up A B A from its host. The absence of A B A in P. italicum after 3 m o n t h s ' growth, with 6 consective transfers, on Czapek's m e d i u m raises a question as to whether A B A is an endogenous p r o d u c t of this fungus, and w h a t role it m a y play in the spread of the infection on the fruit. P. italicum is k n o w n to remain viable for only a short time (less t h a n a year) when ~way from its host (RAPE~ and THOM, 1949). I t seems therefore possible t h a t A B A absorbed b y the fungus from the fruit influences its viability. W o r k is in progress to elucidate these problems. References :BOlgECKA,H., and J. PIENI)~ZEK: Stimulatory effect of abscisic acid on spore germination of Gloeosporium album Osterw. and Botrytis eincrea Pers. Bull. Acad. pol. Sci., C1. V, 16, 657--661 (1968). MILBOR~ow, B.V.: The identification and measurements of (+)-abscisinII [(+)-Dormin] in plants. Planta (Berl.) 76, 93--113 (1967). RAPER, K. :B., and CH. T~o~: A manual of the Penicillia. Baltimore: Williams & Wilkins 1949. Ru~)NIcKI, R. : Studies on abscisic acid in dpple seeds. Planta (Berl.) 86 63--68 (1969). }~. RUDNICKI, H. BO~ECKA,J. PIENI4~I~K Research Institute of Pomology ul. Pomologiczna 22 Skierniewice, Poland
