Ibatsam Khokhar - Academia.edu (original) (raw)

Papers by Ibatsam Khokhar

Pak. J. Weed Sci. Res, 2010

... Prod. 61: 863. Page 6. 456 Irum Mukhtar et al., First report on Cassytha filiformis L. … Dorr... more ... Prod. 61: 863. Page 6. 456 Irum Mukhtar et al., First report on Cassytha filiformis L. … Dorr, I. 1987. The haustorium of Cuscuta-new structural results. ... New York. Kostermans, AJGH 1978. Lauraceae In E. Nasir, E. & SI Ali (eds.) Flora of Pakistan, 118. Karachi. Kuijt, J. 1964. ...

Asian Journal of Experimental …, 2009

Abstract: The Plants and Weeds are screened out for their antibacterial and antifungal activity a... more Abstract: The Plants and Weeds are screened out for their antibacterial and antifungal activity against some gram-positive and gram-negative bacteria's by extracting out their aqueous and methanolic extracts and screened out by analyzing their zone of inhibition. ...

Journal of Plant Pathology

Electronic Journal of Biotechnology, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Pakistan Journal of Weed Science Research, 2013

Powdery mildew fungi are one of the important pathogens and cause a significant damage in various... more Powdery mildew fungi are one of the important pathogens and cause a significant damage in various plants. Ageratum conyzoides L. is a widespread perennial weed having important medicinal and biocontrol properties. In April 2012, a severe outbreak of powdery mildew was observed on A. conyzoides. Powdery mildew symptoms were mainly observed on stem and both sides of young and mature leaves, but not on floral parts. On the basis of morphological characters, the fungus was identified as a Podosphaera xanthii. Pathogenicity test was conducted in green house at 22°C and 80% RH and seven days after inoculation, white powdery mildew colonies appeared on the leaf surface. Fungal colony was reexamined for the confirmation of pathogen. This is the first report of P. xanthii on A. conyzoides in Lahore, Pakistan.

Sarhad Journal of Agriculture, 2012

The phyllospheric microbial communities in Cuscuta pedicelleta Ledeb. and in its host Trifolium a... more The phyllospheric microbial communities in Cuscuta pedicelleta Ledeb. and in its host Trifolium alexandrinum L. were compared to reveal association of microbial distribution between host and parasite. In the present study, stem samples of Cuscuta pedicelleta Ledeb. and healthy leaves of its host plant i.e. Trifolium alexandrinum L. were collected from agriculture area of Lahore, Pakistan, during April 2010. Host leaf/parasite stem washing was used for the isolation of epiphytic and homogenized host leaf/ parasite stem tissue mixture for endophytic microbial population was inoculated separately on 2% MEA and LB medium for bacterial and fungal isolation respectively. Each fungal and bacterial colony was purified and identified on the basis of morphological characteristics and biochemical characteristics. The colonization of the microflora suggested that T. alexandrinum leaf tissue harboured more endophytic and epiphytic bacterial strains than C. pedicelleta. On the other hand, the par...

Journal of Animal and Plant Sciences, 2013

Aak [Calotropis gigantea (L.) R. Br. ex. Ait.] leaf and stem samples infected by leaf spot were c... more Aak [Calotropis gigantea (L.) R. Br. ex. Ait.] leaf and stem samples infected by leaf spot were collected during August and September 2011 from Lahore Pakistan . Infected leaf and stem surfaces were covered with circular to irregular blackish spots. Conidiophores 15-50 × 4-6 x μm, arising from substomatal stroma in loose fascicles of 8 -15, pale to light golden yellow, simple, sometimes geniculate near tip, 0-3 transversely septate. Conidia solitary, thin and smooth walled, cylindric to cylindro-obclavate, 0-8 septate, obconic base, subobtuse to bluntly rounded tip, 10-130 × 4-6 μm. Morphological characteristics and pathogenecity test confirmed the identification as Passalora calotropidis . However, this is the first report of P. calotropidis on Calotropis gigantea from Pakistan.

Plant Disease, 2021

Bidens pilosa L., (spanish needle), is a wild, flowering plant of Asteraceae, that is grown in ga... more Bidens pilosa L., (spanish needle), is a wild, flowering plant of Asteraceae, that is grown in gardens, fields, roadsides, and riverbanks in Fuzhou, China. It is also used in traditional folk medicine for a broad range of ailments in China. In March 2019 and 2020, hundreds of B. pilosa growing along the roadsides, and gardens in the districts of Minhou and Jinshan were observed to be severely affected by a powdery mildew with approximately 80% disease incidence. Symptoms appeared as circular to irregular small white, powdery patches, typically on the adaxial sides of leaves and progressed to coalescent colonies on the leaves. As the disease developed, the infected leaves became wilted and senesced. Mycelia on leaves were superficial and solitary appressoria were slightly to distinctly nipple-shaped. Conidiophores were erect, 120 to 230 × 10 to 12 µm, and produced two to five conidia in chains with a sinuate outline. Foot-cells were erect, cylindrical, and 60 to 110 μm long. Conidia ...

Journal of Hazardous Materials, 2019

Three bacterial consortia, named YC-SY1, YC-BJ1 and YC-GZ1, were enriched from different areas of... more Three bacterial consortia, named YC-SY1, YC-BJ1 and YC-GZ1, were enriched from different areas of China. Bacterial consortia YC-SY1, YC-BJ1 and YC-GZ1 could efficiently degrade triphenyl phosphate (TPhP) (100 mg/ L) by approximately 79.4%, 99.8% and 99.6%, tricresyl phosphate (TCrP) by 90.6%, 91.9% and 96.3%, respectively, within 4 days. And they could retain high degrading efficiency under a broad range of temperature (15-40 ℃), pH (6.0-10.0) and salinity (0-4%). A total of 10 bacterial isolates were selected and investigated their degradation capacity. Among these isolates, two were significantly superior to the others. Strain Rhodococcus sp. YC-JH2 could utilize TPhP (50 mg/L) as sole carbon source for growth with 37.36% degradation within 7 days. Strain Sphingopyxis sp. YC-JH3 could efficiently degrade 96.2% of TPhP (50 mg/L) within 7 days, except that no cell growth was observed. Combined with 16S diversity analysis, our results suggest that the effective components of three bacterial consortia responsible for TPhP and TCrP degradation were almost the same, that is, bacteria capable of degrading TPhP and TCrP are limited, in this study, the most efficient component is Sphingopyxis. This study provides abundant microorganism sources for research on organophosphorus flame retardants (OPFRs) metabolism and bioremediation towards OPFRs-contaminated environments.

Applied Microbiology and Biotechnology, 2019

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants (POPs) widely exist... more Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants (POPs) widely existing in the environment. Arthrobacter sp. YC-RL1 is a biphenyl-degrading bacterium that shows metabolic versatility towards aromatic compounds. A 2-hydroxy-6-oxo-6-phenylhexa-2, 4-dienoate (HOPDA) hydrolase (BphD) gene involved in the biodegradation of biphenyl was cloned from strain YC-RL1 and heterologously expressed in Escherichia coli BL21 (DE3). The recombinant BphD YC-RL1 was purified and characterized. BphD YC-RL1 showed the highest activity at 45°C and pH 7. It was stable under a wide range of temperature (20-50°C). The enzyme had a K m value of 0.14 mM, K cat of 11.61 s −1 , and V max of 0.027 U/mg. Temperature dependence catalysis exhibited a biphasic Arrhenius Plot with a transition at 20°C. BphD YC-RL1 was inactivated by SDS, Tween 20, Tween 80, Trition X-100, DTT, CHAPS, NBS, PMSF, and DEPC, but insensitive to EDTA. Site-directed mutagenesis of the active-site residues revealed that the catalytic triad residues (Ser115, His275, and Asp247) of BphD YC-RL1 were necessary for its activity. The investigation of BphD YC-RL1 not only provides new potential enzyme resource for the biodegradation of biphenyl but also helps deepen our understanding on the catalytic process and mechanism.

International Research Journal of Agricultural Science and Soil Science, 2013

Penicillium spp. produce a variety of beneficial metabolites for plant growth and survival, as we... more Penicillium spp. produce a variety of beneficial metabolites for plant growth and survival, as well as defend their hosts from attack of certain pathogens. In present study 20 Penicillium spp. culture filtrates were screened for growth activity in wheat seedlings. Germination percentage of wheat seeds was enhanced by Penicillium spp. culture extracts. Although, the most active inhibitors of seed gremination were P. dendriticum, P. herquei, P. notatum, and P. oxalicum. Results revealed that he highest seedling root length was attained by P. olivicolor followed by P. bravicompactum and P. spinulosum While, the lowest root growth was attained from P. duclauxii and P. islandicum among other Penicillium culture filtrate treatments. The highest seedling shoot length was observed with P. variabile and P. herquei followed by P. aurantiogriseum - A and P. viridicatum while other Penicillium cultural filtrates significantly suppressed the shoot length as compared to control value (P < 0.05). Fresh and dry weight and of wheat seedling were also significantly higher in Penicillium treatments as compared to control (P < 0.05). Although, in P. dendriticum treatment, fresh and dry weight of seedling was considerably poor. Whereas, P. roquefortii, P. bravicompactum, P. islandicum and P. implicatum had higher values for seedling dry matter. Results revealed that Penicillium spp. are effective for growth parameters and can be used to further investigations and raise the yield of wheat and other cereal crops.

Pakistan Journal of Weed Science Research, 2011

Cuscuta campestris Yunck. is a leafless parasitic weed species belonging to the family Convolvula... more Cuscuta campestris Yunck. is a leafless parasitic weed species belonging to the family Convolvulaceae. During weed survey in July and August 2010, C. campestris was abundantly found parasitizing Capsicum frutescens L. (hot chilli) in the premises of Lahore, Pakistan. Taxonomy and morphological characteristics of C. campestris and its effects on new host have been discussed in this paper. C. campestris is a new pest of C. frutescens, recorded in Lahore region.

Pakistan Journal of Weed Science Research, 2013

Powdery mildew fungi are one of the important pathogens and cause a significant damage in various... more Powdery mildew fungi are one of the important pathogens and cause a significant damage in various plants. Ageratum conyzoides L. is a widespread perennial weed having important medicinal and biocontrol properties. In April 2012, a severe outbreak of powdery mildew was observed on A. conyzoides. Powdery mildew symptoms were mainly observed on stem and both sides of young and mature leaves, but not on floral parts. On the basis of morphological characters, the fungus was identified as a Podosphaera xanthii. Pathogenicity test was conducted in green house at 22°C and 80% RH and seven days after inoculation, white powdery mildew colonies appeared on the leaf surface. Fungal colony was reexamined for the confirmation of pathogen. This is the first report of P. xanthii on A. conyzoides in Lahore, Pakistan.

Japs Journal of Animal and Plant Sciences, 2013

A leaf spot disease was observed on bottle ground [Lagenaria siceraria (Mol.) Standl.] from Septe... more A leaf spot disease was observed on bottle ground [Lagenaria siceraria (Mol.) Standl.] from September to November 2011 in Lahore and Shiekhupura regions. Disease was characterized by irregular to obcircular, medium brown spots with distinct dark brown border on both sides of the leaves. Conidiophores were 2-30 in a divergent fascicle, simple, multiseptate, golden brown, however light paler to subhyaline at the apex, straight to slightly curved 3-5 × 50-300µm, geniculate and unbranched. Conidia were solitary, hyaline, filiform, 1-16 septate, non-constricted at the septa, 2.5-4×20-270µm. The causal organism was isolated and identified as Cercospora citrullina on the basis of pathology and morphological characteristics. It is the first report of C. citrullina on L. siceraria from Lahore, Pakistan.

Pak. J. Weed Sci. Res, 2010

... Prod. 61: 863. Page 6. 456 Irum Mukhtar et al., First report on Cassytha filiformis L. … Dorr... more ... Prod. 61: 863. Page 6. 456 Irum Mukhtar et al., First report on Cassytha filiformis L. … Dorr, I. 1987. The haustorium of Cuscuta-new structural results. ... New York. Kostermans, AJGH 1978. Lauraceae In E. Nasir, E. & SI Ali (eds.) Flora of Pakistan, 118. Karachi. Kuijt, J. 1964. ...

Asian Journal of Experimental …, 2009

Abstract: The Plants and Weeds are screened out for their antibacterial and antifungal activity a... more Abstract: The Plants and Weeds are screened out for their antibacterial and antifungal activity against some gram-positive and gram-negative bacteria's by extracting out their aqueous and methanolic extracts and screened out by analyzing their zone of inhibition. ...

Journal of Plant Pathology

Electronic Journal of Biotechnology, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Pakistan Journal of Weed Science Research, 2013

Powdery mildew fungi are one of the important pathogens and cause a significant damage in various... more Powdery mildew fungi are one of the important pathogens and cause a significant damage in various plants. Ageratum conyzoides L. is a widespread perennial weed having important medicinal and biocontrol properties. In April 2012, a severe outbreak of powdery mildew was observed on A. conyzoides. Powdery mildew symptoms were mainly observed on stem and both sides of young and mature leaves, but not on floral parts. On the basis of morphological characters, the fungus was identified as a Podosphaera xanthii. Pathogenicity test was conducted in green house at 22°C and 80% RH and seven days after inoculation, white powdery mildew colonies appeared on the leaf surface. Fungal colony was reexamined for the confirmation of pathogen. This is the first report of P. xanthii on A. conyzoides in Lahore, Pakistan.

Sarhad Journal of Agriculture, 2012

The phyllospheric microbial communities in Cuscuta pedicelleta Ledeb. and in its host Trifolium a... more The phyllospheric microbial communities in Cuscuta pedicelleta Ledeb. and in its host Trifolium alexandrinum L. were compared to reveal association of microbial distribution between host and parasite. In the present study, stem samples of Cuscuta pedicelleta Ledeb. and healthy leaves of its host plant i.e. Trifolium alexandrinum L. were collected from agriculture area of Lahore, Pakistan, during April 2010. Host leaf/parasite stem washing was used for the isolation of epiphytic and homogenized host leaf/ parasite stem tissue mixture for endophytic microbial population was inoculated separately on 2% MEA and LB medium for bacterial and fungal isolation respectively. Each fungal and bacterial colony was purified and identified on the basis of morphological characteristics and biochemical characteristics. The colonization of the microflora suggested that T. alexandrinum leaf tissue harboured more endophytic and epiphytic bacterial strains than C. pedicelleta. On the other hand, the par...

Journal of Animal and Plant Sciences, 2013

Aak [Calotropis gigantea (L.) R. Br. ex. Ait.] leaf and stem samples infected by leaf spot were c... more Aak [Calotropis gigantea (L.) R. Br. ex. Ait.] leaf and stem samples infected by leaf spot were collected during August and September 2011 from Lahore Pakistan . Infected leaf and stem surfaces were covered with circular to irregular blackish spots. Conidiophores 15-50 × 4-6 x μm, arising from substomatal stroma in loose fascicles of 8 -15, pale to light golden yellow, simple, sometimes geniculate near tip, 0-3 transversely septate. Conidia solitary, thin and smooth walled, cylindric to cylindro-obclavate, 0-8 septate, obconic base, subobtuse to bluntly rounded tip, 10-130 × 4-6 μm. Morphological characteristics and pathogenecity test confirmed the identification as Passalora calotropidis . However, this is the first report of P. calotropidis on Calotropis gigantea from Pakistan.

Plant Disease, 2021

Bidens pilosa L., (spanish needle), is a wild, flowering plant of Asteraceae, that is grown in ga... more Bidens pilosa L., (spanish needle), is a wild, flowering plant of Asteraceae, that is grown in gardens, fields, roadsides, and riverbanks in Fuzhou, China. It is also used in traditional folk medicine for a broad range of ailments in China. In March 2019 and 2020, hundreds of B. pilosa growing along the roadsides, and gardens in the districts of Minhou and Jinshan were observed to be severely affected by a powdery mildew with approximately 80% disease incidence. Symptoms appeared as circular to irregular small white, powdery patches, typically on the adaxial sides of leaves and progressed to coalescent colonies on the leaves. As the disease developed, the infected leaves became wilted and senesced. Mycelia on leaves were superficial and solitary appressoria were slightly to distinctly nipple-shaped. Conidiophores were erect, 120 to 230 × 10 to 12 µm, and produced two to five conidia in chains with a sinuate outline. Foot-cells were erect, cylindrical, and 60 to 110 μm long. Conidia ...

Journal of Hazardous Materials, 2019

Three bacterial consortia, named YC-SY1, YC-BJ1 and YC-GZ1, were enriched from different areas of... more Three bacterial consortia, named YC-SY1, YC-BJ1 and YC-GZ1, were enriched from different areas of China. Bacterial consortia YC-SY1, YC-BJ1 and YC-GZ1 could efficiently degrade triphenyl phosphate (TPhP) (100 mg/ L) by approximately 79.4%, 99.8% and 99.6%, tricresyl phosphate (TCrP) by 90.6%, 91.9% and 96.3%, respectively, within 4 days. And they could retain high degrading efficiency under a broad range of temperature (15-40 ℃), pH (6.0-10.0) and salinity (0-4%). A total of 10 bacterial isolates were selected and investigated their degradation capacity. Among these isolates, two were significantly superior to the others. Strain Rhodococcus sp. YC-JH2 could utilize TPhP (50 mg/L) as sole carbon source for growth with 37.36% degradation within 7 days. Strain Sphingopyxis sp. YC-JH3 could efficiently degrade 96.2% of TPhP (50 mg/L) within 7 days, except that no cell growth was observed. Combined with 16S diversity analysis, our results suggest that the effective components of three bacterial consortia responsible for TPhP and TCrP degradation were almost the same, that is, bacteria capable of degrading TPhP and TCrP are limited, in this study, the most efficient component is Sphingopyxis. This study provides abundant microorganism sources for research on organophosphorus flame retardants (OPFRs) metabolism and bioremediation towards OPFRs-contaminated environments.

Applied Microbiology and Biotechnology, 2019

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants (POPs) widely exist... more Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants (POPs) widely existing in the environment. Arthrobacter sp. YC-RL1 is a biphenyl-degrading bacterium that shows metabolic versatility towards aromatic compounds. A 2-hydroxy-6-oxo-6-phenylhexa-2, 4-dienoate (HOPDA) hydrolase (BphD) gene involved in the biodegradation of biphenyl was cloned from strain YC-RL1 and heterologously expressed in Escherichia coli BL21 (DE3). The recombinant BphD YC-RL1 was purified and characterized. BphD YC-RL1 showed the highest activity at 45°C and pH 7. It was stable under a wide range of temperature (20-50°C). The enzyme had a K m value of 0.14 mM, K cat of 11.61 s −1 , and V max of 0.027 U/mg. Temperature dependence catalysis exhibited a biphasic Arrhenius Plot with a transition at 20°C. BphD YC-RL1 was inactivated by SDS, Tween 20, Tween 80, Trition X-100, DTT, CHAPS, NBS, PMSF, and DEPC, but insensitive to EDTA. Site-directed mutagenesis of the active-site residues revealed that the catalytic triad residues (Ser115, His275, and Asp247) of BphD YC-RL1 were necessary for its activity. The investigation of BphD YC-RL1 not only provides new potential enzyme resource for the biodegradation of biphenyl but also helps deepen our understanding on the catalytic process and mechanism.

International Research Journal of Agricultural Science and Soil Science, 2013

Penicillium spp. produce a variety of beneficial metabolites for plant growth and survival, as we... more Penicillium spp. produce a variety of beneficial metabolites for plant growth and survival, as well as defend their hosts from attack of certain pathogens. In present study 20 Penicillium spp. culture filtrates were screened for growth activity in wheat seedlings. Germination percentage of wheat seeds was enhanced by Penicillium spp. culture extracts. Although, the most active inhibitors of seed gremination were P. dendriticum, P. herquei, P. notatum, and P. oxalicum. Results revealed that he highest seedling root length was attained by P. olivicolor followed by P. bravicompactum and P. spinulosum While, the lowest root growth was attained from P. duclauxii and P. islandicum among other Penicillium culture filtrate treatments. The highest seedling shoot length was observed with P. variabile and P. herquei followed by P. aurantiogriseum - A and P. viridicatum while other Penicillium cultural filtrates significantly suppressed the shoot length as compared to control value (P < 0.05). Fresh and dry weight and of wheat seedling were also significantly higher in Penicillium treatments as compared to control (P < 0.05). Although, in P. dendriticum treatment, fresh and dry weight of seedling was considerably poor. Whereas, P. roquefortii, P. bravicompactum, P. islandicum and P. implicatum had higher values for seedling dry matter. Results revealed that Penicillium spp. are effective for growth parameters and can be used to further investigations and raise the yield of wheat and other cereal crops.

Pakistan Journal of Weed Science Research, 2011

Cuscuta campestris Yunck. is a leafless parasitic weed species belonging to the family Convolvula... more Cuscuta campestris Yunck. is a leafless parasitic weed species belonging to the family Convolvulaceae. During weed survey in July and August 2010, C. campestris was abundantly found parasitizing Capsicum frutescens L. (hot chilli) in the premises of Lahore, Pakistan. Taxonomy and morphological characteristics of C. campestris and its effects on new host have been discussed in this paper. C. campestris is a new pest of C. frutescens, recorded in Lahore region.

Pakistan Journal of Weed Science Research, 2013

Powdery mildew fungi are one of the important pathogens and cause a significant damage in various... more Powdery mildew fungi are one of the important pathogens and cause a significant damage in various plants. Ageratum conyzoides L. is a widespread perennial weed having important medicinal and biocontrol properties. In April 2012, a severe outbreak of powdery mildew was observed on A. conyzoides. Powdery mildew symptoms were mainly observed on stem and both sides of young and mature leaves, but not on floral parts. On the basis of morphological characters, the fungus was identified as a Podosphaera xanthii. Pathogenicity test was conducted in green house at 22°C and 80% RH and seven days after inoculation, white powdery mildew colonies appeared on the leaf surface. Fungal colony was reexamined for the confirmation of pathogen. This is the first report of P. xanthii on A. conyzoides in Lahore, Pakistan.

Japs Journal of Animal and Plant Sciences, 2013

A leaf spot disease was observed on bottle ground [Lagenaria siceraria (Mol.) Standl.] from Septe... more A leaf spot disease was observed on bottle ground [Lagenaria siceraria (Mol.) Standl.] from September to November 2011 in Lahore and Shiekhupura regions. Disease was characterized by irregular to obcircular, medium brown spots with distinct dark brown border on both sides of the leaves. Conidiophores were 2-30 in a divergent fascicle, simple, multiseptate, golden brown, however light paler to subhyaline at the apex, straight to slightly curved 3-5 × 50-300µm, geniculate and unbranched. Conidia were solitary, hyaline, filiform, 1-16 septate, non-constricted at the septa, 2.5-4×20-270µm. The causal organism was isolated and identified as Cercospora citrullina on the basis of pathology and morphological characteristics. It is the first report of C. citrullina on L. siceraria from Lahore, Pakistan.