Biology subjects

Khaliq, I.

Publications and source records attributed to Khaliq, I..

3 recordsLinked to original sources

bioRxiv2025

Uncovering Fusarium species diversity, distribution and pathogenicity associated with cotton and corn fields in recently expanded cotton-growing areas of the Northern High Plains of Texas

The recent expansion of cotton acreage in the Northern High Plains of Texas has raised concerns about the occurrence of a diverse Fusarium community, particularly Fusarium oxysporum f. sp. vasinfectum race 4. We investigated the diversity, distribution, and pathogenicity of Fusarium species in soil samples collected from 26 cotton-corn rotation fields across 10 counties. A total of nine Fusarium species were isolated: F. incarnatum, F. equiseti, F. solani, F. verticillioides, F. proliferatum, F. clavum, F. oxysporum, F. flocciferum, and one unidentified Fusarium sp. The highest species diversity (five species) was observed in Sherman County. Fusarium solani was the most frequently isolated species (39%) across all counties, followed by F. equiseti (22%), while F. flocciferum was the least frequently isolated species (2%). Greenhouse pathogenicity assays showed F. incarnatum caused significantly higher disease severity relative to non-inoculated control on aerial parts of cotton (P=0.0137), while Fusarium flocciferum, F. proliferatum, and F. clavum caused significantly higher disease severity relative to non-inoculated control on roots (P=0.01, P=0.01, P=0.02, respectively). On corn, differences in disease severity were not statistically significant (P>0.05). Fusarium isolates were recovered from both symptomatic and asymptomatic roots following pathogenicity trials, suggesting endophytic colonization. This study revealed a complex Fusarium community capable of cross-infecting cotton and corn, with implications for regional disease management. The absence of Fusarium oxysporum f. sp. vasinfectum race 4 indicates it may not yet have been introduced into the Northern High Plains; however, continued surveillance is warranted given its detection in New Mexico and adjacent counties in Texas.

ecology↗

bioRxiv2020

The role of conidia in the dispersal of Ascochyta rabiei

Ascochyta rabiei asexual spores (conidia) were assumed to spread over short distances ([~]10 m) in a combination of rain and strong wind. The potential distance of conidial spread was investigated in three rainfall and three sprinkler irrigation events. Chickpea trap plants were distributed at the distances of 0, 10, 25, 50 and 75 m from infected chickpea plots before scheduled irrigation and forecast rainfall events. Trap plants were transferred to a controlled temperature room (20 {degrees}C) for 48 h (100% humidity) after being exposed in the field for 2-6 days for rainfall events, and for one day for irrigation events. After a 48 h incubation period, trap plants were transferred to a glasshouse (20 {degrees}C) to allow lesion development. Lesions on all plant parts were counted after two weeks, which gave an estimate of the number of conidia released and the distance travelled. Trap plants at all distances were infected in all sprinkler irrigation and rainfall events. The highest number of lesions on trap plants were recorded closest to the infected plots - the numbers decreased as the distance from the infected plots increased. There was a positive relationship between the amount of rainfall and the number of lesions recorded. A generalised additive model was developed that efficiently described spatial patterns of conidial spread. With further development, the model can be used to predict the spread of A. rabiei. This is the first systematic study to show that conidia distribute A. rabiei over longer distances than previously reported.

plant biology↗

bioRxiv2017

Metabolism constrains bird and mammal ranges and predicts shifts in response to climate change

AimWe test whether physiological constraints on maximum metabolic rate and the factor by which endotherms can elevate their metabolism (metabolic expansibility) govern cold range limits for mammal and bird species.\n\nLocationGlobal\n\nMethodsWe examine metabolic expansibility at the cold range boundary (MEO_SCPLOWCRBC_SCPLOW) and its trait predictors and then use MEO_SCPLOWCRBC_SCPLOW to project range shifts for 210 mammal and 61 bird species.\n\nResultsWe find evidence for metabolic constraints: the distributions of metabolic expansibility at the cold range boundary peak at similar values for birds (2.7) and mammals (3.2). The right skewed distributions suggest some species have adapted to elevate or evade metabolic constraints. Mammals exhibit greater skew than birds, consistent with their diverse thermoregulatory adaptations and behaviors. Mammal and bird species that are small and occupy low trophic levels exhibit high levels of MEO_SCPLOWCRBC_SCPLOW. Mammals with high MEO_SCPLOWCRBC_SCPLOW tend to hibernate or use torpor. Predicted metabolic rates at the cold range boundaries represent large energetic expenditures (>50% of maximum metabolic rates). We project species to shift their cold range boundaries poleward by an average of 3.9{degrees} latitude by 2070.\n\nMain conclusionsOur analysis suggests that metabolic constraints provide a viable mechanism for projecting cold range boundaries and range shifts in response to climate change for endotherms.

ecology↗