Severns Paul M, Oliver Jonathan E
Department of Plant Pathology, University of Georgia, Athens, GA 30602, USA.
Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA 30602, USA.
Pathogens. 2024 Oct 15;13(10):904. doi: 10.3390/pathogens13100904.
(Xf), a gram-negative bacterium, is a notorious, world-wide plant pathogen with an extended latent period that presents a challenge for early disease detection and control interventions. We used thermal imaging of tissue-cultured, experimentally Xf-infected blueberry plants to identify visually pre-symptomatic leaves and compared the minimum force required to dislodge symptomatic leaves from infected plants to leaves on uninfected (control) blueberry plants. For two different blueberry cultivars and one pathogenic isolate of , we found no statistical difference between the mean downward force for leaf dislodgement, regardless of symptom category, on Xf-infected blueberry plants. That force was about 50% to 30% of the mean force to remove leaves from uninfected blueberry plants depending on the cultivar. These results indicate that visually pre-symptomatic leaves may be just as readily lost under field conditions as visually symptomatic leaves, both of which are important for early disease detection. Second, some thermally symptomatic and visually symptomatic leaves appeared to self-prune (abscise) and this may be an unrecognized early symptom of Xf-caused disease in blueberries. Last, it is possible that the self-pruning of visually asymptomatic leaves may occur in other agriculturally and culturally important plants infected by but this remains an unrecognized early disease symptom.
(Xf)是一种革兰氏阴性细菌，是一种臭名昭著的全球植物病原体，其潜伏期较长，这给早期疾病检测和控制干预带来了挑战。我们对组织培养的、经实验感染Xf的蓝莓植株进行热成像，以识别视觉上无症状的叶片，并比较从感染植株上摘除有症状叶片所需的最小力与未感染（对照）蓝莓植株上叶片的最小力。对于两个不同的蓝莓品种和一种Xf致病分离株，我们发现，无论症状类别如何，Xf感染的蓝莓植株上叶片脱落的平均向下力之间没有统计学差异。根据品种不同，该力约为从未感染蓝莓植株上摘除叶片平均力的50%至30%。这些结果表明，在田间条件下，视觉上无症状的叶片可能与视觉上有症状的叶片一样容易脱落，这两者对早期疾病检测都很重要。其次，一些热症状和视觉症状的叶片似乎会自行修剪（脱落），这可能是蓝莓中Xf引起疾病的一种未被认识的早期症状。最后，视觉上无症状的叶片自行修剪可能发生在其他受Xf感染的具有农业和文化重要性的植物中，但这仍然是一种未被认识的早期疾病症状。
