Phenotypic differences and host interaction dynamics of the Botrytis cinerea UCA992 isolate compared with the reference isolate B05.10

Abstract The Botrytis cinerea B05.10 serves as a universal standard strain. However, the wild-type isolates provide necessary insight into alternative physiological strategies. Here, a comparative phenotypic evaluation of the Botrytis cinerea UCA992 wild-type isolate against the reference strain B05.10 is reported. To achieve this, a comprehensive multi-trait approach was conducted, evaluating asexual conidiation capacity, baseline mycelial expansion kinetics, in vitro resilience to osmotic and oxidative stressors, and ex vivo necrotrophic virulence across host plant tissues. The UCA992 isolate exhibited approximately a twofold increase in conidia production, a lower baseline radial growth rate and higher susceptibility to osmotic and oxidative stressors than B05.10. Moreover, ex vivo pathogenicity assays showed that UCA992 is substantially more aggressive, producing necrotic lesions up to 2.3 times larger in early interaction with Nicotiana tabacum and Solanum lycopersicum . These findings suggest a profound physiological trade-off in the UCA992 isolate, where vegetative vigour and in vitro stress resilience are compromised in favour of maximized asexual dissemination and intense necrotrophic aggressiveness.