ndian Journal of Experimental Biology vol. 38, Janu ary 2000, pp . 84-87 Fungal metabolites from Aspergillus niger AN27 related to plant growth promotion Goutam Mondal* 1 , Prem Dureja 2 & Bi nee ta Sen** 1 1 Division of Plant Patholo gy and 2 Divi s ion of Agricultural Chemicals, Indian Agricult ur al Researc h ln sti lulc, New Delhi 110 012, In dia Rece ived I Apri/ 1999; revised 20 Septemb er /99 9 Two met abo lites ha ve been isolated from AsJJergillus niger AN27, a biocontrol agent, and id entilicd as 2-carhmymethyl 3-n-hexyl mal eic acid (co mp ound I) and 2-mcthylene-3-hexylbutanedioic acid (co mp ou nd 2). Th e ir biological activities related to crop growth promotion have been assayed. Both the compounds increased germination and improved crop vigour. Compound I wa s more effective for increase in germination and shoot length, whereas compound 2 had relati vely greater role in in c reasing the root length and biomass of ca ul iflower seedlin gs . Plant vigo ur is an imp ortant factor in resis tance of crop to severa l diseases' . Introduced biocontrol agents, mostly bacteria only have been reported to increase plant vigour as we ll as yield 2 - 6 . Amo ng the fungal bi ocontro l agents, Trichoderma spp. and some unidentified sporu lating and non spo rulating fungal isolates have been reported to promote plant growth d " lb d" 7 " 1 ? an suppress sot orne tseas es -_ Funga l metabolites relat ed to plant growth promotion have been identified in a few cases 13 - 15 • Alma ssi et al. 16 have re port ed some seco ndar y metabolites viz. 2-carboxymethyl 3- n-hexyl maleic acid anhydrid e, 2-met hylene-3- hexylbuta ned ioic acid and 2-methyle ne-3-(6-hydroxy hexy l)-butanedioic acid which they isolated from an unsp ec ific isolate of A. niger. But none of these fungi has been reporte d to have biocontrol ability. Efficacy of A. nig er strain AN27 has been tested against different soi l bome funga l plant pathogens in laboratory and in field The principal ant ifun ga l compou nd has been iso lated from this stra in and identifi ed as trans and cis-4(3acetoxy-6-met hoxy-2- hydroxyphenyl)-2-methoxy - butanolide 20 . Besides co ntrolling disease, the isolate also promotes growt h and crop yie ld 18 . Th e prese nt pap er reports the iso lation of two compou nds from the biocontrol agent, A. niger st rain AN27 and their plant growt h promoting activ it y. *Present address-Pulses and Oil sccds Research Station, Berhampore, Murshidabad-742 I0 I Indi a ** Correspondent auth or Test crop-Cau lifl ower cv. Pusa : mow ball K I obtained from the Division of Vege table Crops, of th e Institute was used as the tes t crop for bi oassay. Isolation of secondarv tn etuh(l/i /es-G rowth promoting compounds were is olat ed as described earlier 16 • Aspergillus niger AN27 was in oc ulat ed in Sabouraud broth med ium ( 40g, dex tr ose; I Og, peptone in I litre H 2 0, pH 5.6)@ 2ml of 2.5x lOR cfu mr' in eac h of 500m l med ium lots . The flasks wer e incubated in a shaker BOD at I SO rpm for 7days at 30°C. T he culture broth was filtered thr ough a Whatman filter paper (No.3) and the filtrate was ext racted with ethylacetate. The orga n ic la yer was separated, dried ove r anhydrous sodium sulphate and concentrated on a rotary vacuum eva p orator. The da rk brown oi ly residu e obtained s howed the presenc e of three metabo lites on thin la ye r chromatog raphy us in g hexane :ethylacetat e:ace ti c acid (60 :40:0 .1 ). These metabolite s were separated by co lumn chr oma to- grap hy on silica ge l eluting with dich loromethan e to et hylacetate. The se parat ed met abolit es were characterised by nuclear resona nce (NM R) and ma ss spectroscopy. was ca rried out on a th ermo-separation product model spectra system P2000, hi gh perfo rmance I iqu id chr omato- graphy (HPLC), equipped with variabll: wavelength UV-1 50, UV-V IS d<:!tect or and a Rh eody ne inj ec t or (20 J..ll loop). 1 H-NMR spectra wer e reco rd ed on Variati EM 360L (60 MHz) and Bruker 400 AC (400 MHz) instruments . Deute ro-chloroform (CDCI 1 ) and pyridine were used as so lvents and tetra methylsilane