Cervantes Kimberly, Hilton Angelyn E, Stamler Rio A, Heerema Richard J, Bock Clive, Wang Xinwang, Jo Young-Ki, Grauke L J, Randall Jennifer J
Molecular Biology and Interdisciplinary Life Sciences, New Mexico State University, Las Cruces, NM, United States.
United States Department of Agriculture, Southern Plains Agricultural Research Center, Pecan Breeding and Genetics, Somerville, TX, United States.
Front Plant Sci. 2022 Apr 8;13:780335. doi: 10.3389/fpls.2022.780335. eCollection 2022.
Pecan bacterial leaf scorch, caused by subsp. , is an economically significant disease of pecan with known detrimental effects on the yield of susceptible cultivars. In this study, endosperm was harvested from developing pecan seeds, and direct qPCR and sequencing were used to detect and confirm the presence of . DNA was isolated from mature seeds originating from seven trees, revealing a positivity rate up to 90%, and transmission of from infected seed to the germinated seedlings was found to be over 80%. Further epidemiological analyses were performed to determine where localizes in mature seed and seedlings. The highest concentrations of DNA were found in the hilum and outer integument of the seeds and the petioles, respectively. High-, medium-, and low-density seeds were harvested to determine the impact of the bacterium on seed density and seedling growth rate. The growth rate of seedlings originating from low-density seeds was significantly reduced compared to the medium- and high-density seeds. Despite the increased growth and germination rates, the high-density seed group had a greater proportion of samples that tested positive for the presence of by qPCR. The results demonstrate the ability of to colonize developing seeds and be efficiently transmitted from well-developed seeds to germinated seedlings. Continued research is needed to understand the plant-microbe interactions involved in the colonization of pecan seeds by and to develop effective phytosanitary approaches to reduce the risks posed by seed transmission.
山核桃细菌性叶焦枯病由[具体亚种名称]引起，是山核桃一种具有经济重要性的病害，对易感品种的产量有已知的不利影响。在本研究中，从发育中的山核桃种子收获胚乳，并使用直接定量聚合酶链反应（qPCR）和测序来检测和确认[具体细菌名称]的存在。从七棵树的成熟种子中分离出DNA，阳性率高达90%，并且发现[具体细菌名称]从受感染种子传播到发芽幼苗的比例超过80%。进行了进一步的流行病学分析，以确定[具体细菌名称]在成熟种子和幼苗中的定位。分别在种子的种脐和外种皮以及叶柄中发现了最高浓度的[具体细菌名称]DNA。收获了高密度、中密度和低密度种子，以确定该细菌对种子密度和幼苗生长速率的影响。与中密度和高密度种子相比，低密度种子来源的幼苗生长速率显著降低。尽管生长和发芽率有所提高，但高密度种子组中通过qPCR检测出[具体细菌名称]呈阳性的样本比例更高。结果表明[具体细菌名称]能够定殖于发育中的种子，并能有效地从发育良好的种子传播到发芽的幼苗。需要继续开展研究，以了解[具体细菌名称]定殖山核桃种子所涉及的植物-微生物相互作用，并制定有效的植物检疫方法，以降低种子传播带来的风险。
