China is considering imposing a devastating 80.5% tariff on Australian barley imports. While that would be a blow to Australia's industry, other countries would likely benefit. The proposed tariff is a result of an ongoing anti-dumping investigation into barley exported from Australia that China’s Ministry of Commerce initiated back in November 2018. It also comes amid heightened tensions between the countries that resulted in China suspending some meat imports from Australia. At the start of the investigation, China’s barley industry requested an anti-dumping tariff of 56.14%. The proposed rate may increase to 73.6% following investigations by Chinese authorities. This rate coupled with a “subsidy margin” of up to 6.9% would amount to a tariff of 80.5%, effectively putting an end to Australian barley sales to China. The investigation is scheduled to finalize by May 19, 2020.
Last week USDA released import and export trade data for March 2020, an important new piece of information in understanding the impact of the COVID-19 outbreak. While the first stay-at-home orders didn’t begin until mid-March, concerns about the virus began several weeks before, impacting businesses and consumer purchasing behavior nearly the entire month of March. While we have been able to fairly immediately measure some domestic impacts, like those on the stock market, unemployment and store closings to name a few, the effect on international trade has been a bit harder to gauge because that data is on a two-month time delay. However, this new data helps bring the trade picture into focus. Overall, the U.S. had a negative ag trade balance of $501 million in March 2020, down sharply from March 2019, when the balance was positive $70 million. March 2020’s year-over-year decline was fueled by a 1% decrease in exports, while imports rose 3%. On a regional basis, the U.S. saw a decline in net exports in all regions, except for South Asia. In many regions, both exports and imports in March 2020 were higher than in March 2019, though the growth in imports outpaced exports. For example, in North America, U.S. exports rose $179 million, while imports rose $262 million, leading to a net export loss of $83 million in March 2020 compared to March 2019. Unsurprisingly, the region with the largest decline in net exports was East Asia, which includes China.
Peppers are one of the most important vegetables and spices in the world and their fruits are used in a range of food dishes, to provide aroma and flavor. Pungency has been largely studied, while studies on the volatile fraction are more recent and less diverse. A considerable varietal diversity among peppers has been reported in terms of the aroma quality and the qualitative and quantitative variation in the volatile fraction, particularly in fully ripe fruits, which encompass most diverse food applications and aroma profiles. Thus, a study was designed to study the inheritance of the volatile fractions in peppers and to determine if they can be improved by breeding strategies. The volatile fraction of 175 samples of ripe fruits from a diverse collection of peppers, encompassing a range of varietal types and aroma qualities, were isolated by headspace-solid-phase microextraction and analyzed by gas chromatography–mass spectrometry. A diverse profile of volatiles including terpenoids, esters, alkanes, and several aldehydes and alcohols, was found among the evaluated accessions. Findings indicated that, in most cases, hybridization provided higher amounts of total volatiles and a more complex composition, particularly in the pericarp. In addition, the volatile fraction can be inherited from the parents to the offspring, as most individual volatiles in hybrids, especially major volatiles, were present in at least one of the parents, following intermediate (levels between parents) or transgressive (levels higher than the best parent) inheritance. De novo compounds (present in the hybrid, absent in the parents) were found in many samples. Comparatively, placental tissues had higher total and individual volatile levels compared with the pericarp in most parent accessions and hybrids, which must be considered by breeders if this part of the fruit is included in food formulations. By combining parent lines with complementary volatile fractions, hybridization offers a feasible method to improve the volatile composition of ripe fruits in peppers.
Lettuce is one of the top ten vegetables cultivated in the United States and for good reason. Romaine, iceberg, leaf and butterhead types of lettuce are staples in refrigerators around the world. Used as a basis for salads, as a topping for burgers and sandwiches, as a bread substitute for wraps, and even as a garnish for elegantly plated cuisines, lettuce serves as a recommended source of extra nutrition, much-needed fiber, and fewer added calories to diets. But the crop has experienced devastation nationwide with the emergence of the deadly Bacterial Leaf Spot (BLS), a disease caused by a pathogen known as Xanthomonas campestris pv. vitians (Xcv). This unpredictable disease can cause severe economic losses devastated entire harvests. Currently, there is no meaningful control method. University of Florida scientists at Everglades Research and Education Center in Belle Glade, along with other land grant universities and federal agencies, have been at the forefront of research since the disease emerged. Focus has been on studying BLS and how it destroys lettuce. Now an $850,816 grant will fund the continuation of research led by UF/IFAS scientists in a multistate endeavor with Pennsylvania State University and the United States Department of Agriculture-Agricultural Research Services (USDA-ARS) Salinas, CA. The grant, managed by the Florida Department of Agriculture and Consumer Service (FDACS) through the Specialty Crop Multi State Program of the USDA-AMS to UF/IFAS, is designated for the study of disease resistance in lettuce, to boost cultivar variations that are BLS-resistant through breeding and genetics, and to research BLS-lettuce interaction. Germán V. Sandoya-Miranda, assistant professor of lettuce breeding and genetics at Everglades Research and Education Center, overseeing the project as principal investigator, has been researching BLS since 2016. Sandoya is joined by UF’s Calvin Odero, UF/IFAS associate professor of agronomy specializing in weed science as co-lead, UF/IFAS Extension Palm Beach staff, Pennsylvania State University’s Carolee Bull, a professor and department head of Department of Plant Pathology, Maria Gorgo-Gourovitch, an Extension educator and Plant Pathology affiliate instructor at Pennsylvania State University, and lettuce plant breeder and geneticist Ivan Simko of the USDA-ARS in California. “This is the first time that experts in plant breeding, genetics, bacteriology, and weed science partner to develop sustainable and long-term solutions to battle an unpredictable and devastating disease in lettuce”, said Sandoya. “I have intentionally brought together the leading experts representing the strongest possible group to work on this disease for a variety of geographic impacted areas and assorted farm-size growers.” The United States is the second-largest producer of lettuce in the world. Harvested on more than 342,965 acres across the nation, it represents a $2 billion industry mostly situated in California, Arizona, and Florida, according to the 2017 U. S. Department of Agriculture (USDA) Census Data. Lettuce is also an important component of sales for small diversified farms in the Mid-Atlantic and everywhere else nationally. In Florida, more than 9,300 acres harvest lettuce throughout the state between September and May, with a majority of the production occurring in the Everglades Agricultural Area located just below Lake Okeechobee in Palm Beach County. “In this project, we are using plant breeding and genetic approaches to study disease resistance and the various interactions between the lettuce and the pathogen,” Sandoya added. “For the growers, we will develop resistant cultivars, because of the warmer conditions in the state that make growing in Florida more complicated. Another objective in the research will examine the potential of weeds as a secondary cause of the disease in Florida, he added. Emma Rosenthal, a graduate student working with Bull, is interested in understanding the specificity of the plant-pathogen interactions. She is hoping to use genes involved in specificity to develop methods for detection and quantification of strains of the pathogen causing disease on different varieties. Gorgo-Gourovitch will also ensure that knowledge from this project is disseminated as bilingual extension products in keeping with Penn State’s Latinx Agriculture initiatives. USDA-ARS will be involved in identifying resistance genes in cultivated and wild accessions of lettuce and introduce these genes into the breeding program.
5月25日，华中农大油菜团队杨光圣和洪登峰教授课题组在The Plant Journal杂志发表题为“Molecular mechanisms underpinning the multiallelic inheritance of MS5 in Brassica napus”的研究论文，揭示了一个在油菜杂交种制种中被广泛应用的MS5基因调控的细胞核雄性不育系统的复等位遗传机制。 细胞核雄性不育是油菜杂种优势利用的重要途径之一，也是开展轮回选择的重要桥梁性状。其中，Yi3A类型的细胞核雄性不育系统因其育性受到同一基因座位的三个复等位基因MS5a（恢复基因），MS5b（不育基因）和MS5c（临保基因）控制，且三者之间具有MS5a > MS5b > MS5c的显隐性关系，可方便实现油菜的“三系化”制种。2016年，该课题组成功克隆了MS5位点的三个复等位基因，并和中科院遗传所程祝宽团队合作解析了不育系中减数分裂进程异常的细胞学机制（Xin et al., 2016. Plant Cell），但复等位遗传背后的分子机制却一直不为人所知。 本研究中，通过CRISPR/Cas9基因编辑证明恢复基因MS5a和临保基因MS5c都是油菜育性维持所必需的，基因缺失后表现出与不育系相同的减数分裂异常表型。MS5a和MS5c基因在恢复或保持MS5b不育方面功能出现分化的主要原因是它们编码区序列的差异，其次为启动子区的不同造成的表达量差异。雄性不育基因MS5b编码一个嵌合蛋白，包含完整的coiled coil（CC）结构域，但缺失了整个MS5 superfamily domain（MSD）。MS5a或MS5c蛋白可以通过CC结构域形成同源二聚体，MS5b则能通过残留的CC结构域与MS5正常功能蛋白竞争性结合，形成无功能的二聚体。由于MS5b和MS5c表达量几乎相同，在MS5bMS5c杂合材料中，无功能的异源二聚体占优势，从而使得油菜减数分裂异常，遗传上表现为MS5b对MS5c的显性负效应。而在MS5aMS5b杂合单株中，由于MS5a的高表达，大剂量MS5a蛋白的积累保证了减数分裂的正常进行。这一结果为遗传学上完全显隐性关系的复等位遗传现象提供了一个新的分子机制解释。同时，MS5复等位遗传分子机制的解析，也为MS5调控的雄性不育在油菜及芸薹属其他物种中的应用奠定了基础。 生命科学技术学院博士后辛强博士为论文第一作者，植物科技学院洪登峰教授为论文通讯作者。校级蛋白质平台为该研究的开展提供了大力支持。本研究受到了国家重点研究开发、国家自然科学基金、华中农业大学科技自主创新基金和博士后创新人才支持计划的资助。 据悉，该团队还与生命科学技术学院殷平教授合作，通过结构生物学方法解析了MS5蛋白中关键功能结构域MSD的晶体结构。近期该研究成果在FEBS letters杂志上以“Structural analysis of the meiosis-related protein MS5 reveals non‐canonical papain enhancement by cystatin-like folds”为题发表。进化分析显示，（MS5 family：Pfam, PF04776），除减数分裂相关的MS5基因外，目前尚未有该家族其他基因的功能报道。本研究发现MS5属于一个十字花科特异的基因家族，其核心结构域MSD呈现一种典型的类-cystatin（半胱氨酸蛋白酶抑制剂）结构，包括一个α螺旋围绕着4或5个反向平行的β折叠。但与半胱氨酸蛋白酶抑制剂功能不同的是，MSD可以通过对木瓜蛋白酶的变构激活，促进而不是抑制半胱氨酸蛋白酶的活性。该研究首次在植物中解析了MSD的结构并揭示了该家族蛋白保守的半胱氨酸蛋白酶促进活性。