Ficus benjamina , commonly called tears fig or Benjamin fig , is a flowering flora in the kin Moraceae . It is widely turn as an ornamental tree or hedgerow . During the spring of 2019 , yellowing and dieback of F. benjamina were keep in unlike regions of Hamedan Province , Iran ( Fig . 1 ) .
trope 1 : Yellowing and dieback on plants infected with Diaporthe foeniculina .
To insulate the causal being from septic tissues , small twig pieces were cut from the boundary between morbid and healthy tissue paper , airfoil - sterilised for one minute in 1 % ( westward / v ) sodium hypochlorite , rinsed three time with sterile water , dried on sterile filter paper , reassign to potato dextrose agar ( PDA ; Merck , Darmstadt , Germany ) and incubated at 25 ° coulomb in the dark . Five to seven days after incubation , fungal isolates were obtained from symptomatic tissues . The morphologic characteristics were mold based on pure cultures grown on PDA . Colony word structure , sizing and shape of 30 conidiospore and conidiophores were recorded after seven days incubation . colony on PDA were slowly - growing and livid with sparse aerial mycelium ( Fig . 2 ) . After 15 days , conidioma ( pycnidium ) production was observed ( Fig . 3 ) . Microscopic recognition was done using a Leica DMLB microscope . Pycnidia globose to subglobose with an elongated and black neck . conidiophore hyalin , sub - cylindric and cylindrical , filiform , ramify above the septa , tapering towards the acme , 1 - 3 septate , ( 19-)20 - 28(-32 ) × 2(-3 ) μm . Conidiogenous cells hyaline , subcylidrical and filiform , straight , slightly tapering towards the apex , collarette not flared , with large periclinial thickening , ( 10-)11 - 15(-17 ) × 2(-3 ) μm . Alpha conidium aseptate , hyaline , smooth , ellipsoidal or fusiform and 8 - 9 × 2 - 2.5 μm ( Fig . 4a ) . genus Beta conidia aseptate , filiform , more or less curving and 25 - 29 × 1 - 1.5 μm ( Fig . 4b ) . Based on structural and cultural characteristic , the isolates were identify as Diaporthe foeniculina ( Sacc . ) Udayanga & Castl . (= Phomopsis foeniculina ( Sacc . ) Udayanga & Castl ) ( Udayanga et al . , 2014 ) . Representative acculturation were deposited in the culture collection of the Iranian Research Institute of Plant Protection ( IRAN3161C ) .
Figure 2 : Colony morphology of Diaporthe foeniculina after 15 days on potato dextrose nutrient agar .
Figure 3 : Stromatic structures of Diaporthe foeniculina after 15 day on potato dextrose nutrient agar .
Figure 4 : a ) Alpha - conidia and b ) beta - conidium of Diaporthe foeniculina .
In club to confirm Koch ’s postulate , pathogenicity trial were performed on sound seedling in testing ground conditions at 25 ° C with raw daylight as follows . theme were wounded using a aseptic 5 mm diam metal cork bore bit . A mycelial plug ( 5 mm diameter ) hold from the margin of a seven - day - old fungous settlement ( IRAN 3161C ) was placed in the lesion . The wound was wrapped with moldable motion-picture show and for the control plants , a plug of sporty PDA was direct in the combat injury . Two week after inoculation , symptoms were observed on the inoculated plant while no symptom appear on the control condition . Diaporthe foeniculina was systematically reisolated from artificially infected plants ( Fig . 5 ) .
Figure 5 : ascendancy plant ( left ) and yellow and dieback on an unnaturally infect industrial plant ( right ) .
To confirm the morphological identification , one isolate ( IRAN 3161C ) was select for molecular analysis . Genomic DNA was extracted from mycelium of a pure culture as described by Sharma et al . ( 2002 ) . Molecular recognition was performed base on the beta - tubulin gene which was sequenced using primer BT2A and BT2B ( Glass & Donaldson , 1995 ) . BLAST search of a 566 bp successiveness ( GenBank Accession No . MG367462 ) present 100 % identity with D. foeniculina ( KC843213 ) . These run effect confirmed D. foeniculina to be the causal broker of the newly observe disease on F. benjamina . To our cognition , this is the first report card of yellowing and dieback because of D. foeniculina on F. benjamina ( Farr & Rossman , 2020 ) .
Source : BSPP ( A. Esmaeilzadeh , D. Zafari and S. Bagherabadi )
