International Journal of Plant Biology

Anthracnose is one of the most destructive diseases of avocado worldwide; however, foliar infections remain poorly documented in Peru. We investigated the etiology of necrotic leaf lesions observed in avocado plantations in Amazonas and assessed the in vitro antifungal activity of two Piper essential oils (EOs). Incidence was quantified in a 420-tree plot (n = 150 plants). Two representative isolates (MGS03, MGS04) were obtained from symptomatic leaves and characterized by morphology and multilocus sequencing (ITS, CHS-1, ACT, and TUB2). Maximum-likelihood phylogeny within the C. gloeosporioides species complex clustered with C. fructicola. Pathogenicity tests on detached leaves (unwounded inoculation) reproduced field symptoms and fulfilled Koch’s postulates. The antifungal activity of Piper carpunya and P. aduncum EOs (50–1000 µL L⁻¹) was evaluated using poisoned-medium assays, revealing a strong dose-dependent inhibition of mycelial growth. Inhibition reached >89.8% at 500 µL L⁻¹ and ~100% at 1000 µL L⁻¹, with P. aduncum showing slightly higher activity. This study provides the first confirmed record of C. fructicola associated with necrotic leaf lesions in avocado in Peru and demonstrates the promising antifungal potential of Piper EOs as eco-friendly candidates for anthracnose management.

Cynipid gall wasps are known for their ability to manipulate host plant development, redirecting undifferentiated tissues into complex, highly specialised structures. In this study, we investigated how Andricus quercustozae larvae manipulate axillary bud tissues of Quercus virgiliana across four key stages of gall development: initiation, differentiation and growth, maturation, and lignification. Using detailed histological analyses, we characterised progressive tissue differentiation within galls, focusing on the organisation of nutritive, protective, and vascular tissues. Gall development was marked by sustained hyperplasia and hypertrophy, extensive vascular proliferation, and progressive cell wall lignification, resulting in a complex organ optimised for larval nutrition and protection. To complement these anatomical observations, we conducted a preliminary transcriptomic comparison between gall tissue and unmodified leaf tissue. Gene expression analyses revealed suppression of photosynthesis-related functions and coordinated modulation of developmental, regulatory, and metabolic pathways, consistent with a transition from assimilatory leaf tissue to a specialised nutrient sink. Integration of anatomical and transcriptomic evidence supports a model in which cynipid gall wasps intervene at key regulatory nodes of bud development, progressively reprogramming host tissues to form a functionally autonomous gall. These findings provide new insight into the extended phenotype and highlight the plasticity of plant developmental programmes under insect control.

Lavender has been cultivated in Bulgaria for over a century. The high essential oil content and quality of Bulgarian lavender varieties have established the country as a leading global producer. Studies into the crop’s genetic diversity are essential for selecting varieties best suited to specific environmental conditions, maximizing resilience and yield. Therefore, identifying appropriate genetic markers to monitor lavender diversity is a key prerequisite for developing effective crop selection strategies, particularly in response to the challenges posed by global climate change. In this study, we evaluate the versatility of markers for assessing genetic diversity of lavender genotypes. A total of 96, 97 and 96 bands were recorded using the 13 Start Codon Targeted Polymorphism (SCoT), 13 Inter-Simple Sequence Repeat (ISSR) and 14 Cis-Element Aligned Polymorphism (CEAP) primers, respectively. All amplification programs used were successful in the studied genotypes. Additionally, four informative primers of each marker system were applied for assessment of the within-field genetic variability in two lavender plantations from Bulgaria. This is the first report on the combined use and comparison of CEAP, SCoT and ISSR primers in lavender genotypes in Bulgaria.