Jasmonate-dependent plant defense restricts thrips performance and preference

<p>Abstract</p> <p>Background</p> <p>The western flower thrips (<it>Frankliniella occidentalis </it>[Pergande]) is one of the most important insect herbivores of cultivated plants. However, no pesticide provides complete control of this species, and insecticide resistance has emerged around the world. We previously reported the important role of jasmonate (JA) in the plant's immediate response to thrips feeding by using an <it>Arabidopsis </it>leaf disc system. In this study, as the first step toward practical use of JA in thrips control, we analyzed the effect of JA-regulated <it>Arabidopsis </it>defense at the whole plant level on thrips behavior and life cycle at the population level over an extended period. We also studied the effectiveness of JA-regulated plant defense on thrips damage in Chinese cabbage (<it>Brassica rapa </it>subsp. <it>pekinensis</it>).</p> <p>Results</p> <p>Thrips oviposited more on <it>Arabidopsis </it>JA-insensitive <it>coi1-1 </it>mutants than on WT plants, and the population density of the following thrips generation increased on <it>coi1-1 </it>mutants. Moreover, thrips preferred <it>coi1-1 </it>mutants more than WT plants. Application of JA to WT plants before thrips attack decreased the thrips population. To analyze these important functions of JA in a brassica crop plant, we analyzed the expression of marker genes for JA response in <it>B. rapa</it>. Thrips feeding induced expression of these marker genes and significantly increased the JA content in <it>B. rapa</it>. Application of JA to <it>B. rapa </it>enhanced plant resistance to thrips, restricted oviposition, and reduced the population density of the following generation.</p> <p>Conclusion</p> <p>Our results indicate that the JA-regulated plant defense restricts thrips performance and preference, and plays an important role in the resistance of <it>Arabidopsis </it>and <it>B. rapa </it>to thrips damage.</p

Interfamily Transfer of Dual NB-LRR Genes Confers Resistance to Multiple Pathogens

A major class of disease resistance (R) genes which encode nucleotide binding and leucine rich repeat (NB-LRR) proteins have been used in traditional breeding programs for crop protection. However, it has been difficult to functionally transfer NB-LRR-type R genes in taxonomically distinct families. Here we demonstrate that a pair of Arabidopsis (Brassicaceae) NB-LRR-type R genes, RPS4 and RRS1, properly function in two other Brassicaceae, Brassica rapa and Brassica napus, but also in two Solanaceae, Nicotiana benthamiana and tomato (Solanum lycopersicum). The solanaceous plants transformed with RPS4/RRS1 confer bacterial effector-specific immunity responses. Furthermore, RPS4 and RRS1, which confer resistance to a fungal pathogen Colletotrichum higginsianum in Brassicaceae, also protect against Colletotrichum orbiculare in cucumber (Cucurbitaceae). Importantly, RPS4/RRS1 transgenic plants show no autoimmune phenotypes, indicating that the NB-LRR proteins are tightly regulated. The successful transfer of two R genes at the family level implies that the downstream components of R genes are highly conserved. The functional interfamily transfer of R genes can be a powerful strategy for providing resistance to a broad range of pathogens

Selective deployment of virulence effectors correlates with host specificity in a fungal plant pathogen

なぜ病原菌は特定の作物にのみ感染するのか --植物病原菌の宿主特異性の鍵因子--. 京都大学プレスリリース. 2023-03-23.Fungus has a host of issues: KyotoU discovers how toxic fungi target specific host plants. 京都大学プレスリリース. 2023-06-07.The hemibiotrophic fungal plant pathogen Colletotrichum orbiculare is predicted to secrete hundreds of effector proteins when the pathogen infects cucurbit crops, such as cucumber and melon, and tobacco (Nicotiana benthamiana), a distantly related Solanaceae species. Here, we report the identification of sets of C. orbiculare effector genes that are differentially required for fungal virulence to two phylogenetically distant host species. Through targeted gene knockout screening of C. orbiculare ‘core’ effector candidates defined based on in planta gene expression, we identified: four host-specific virulence effectors (named effector proteins for cucurbit infection, or EPCs) that are required for full virulence of C. orbiculare to cucurbit hosts, but not to the Solanaceae host N. benthamiana; and five host-nonspecific virulence effectors, which collectively contribute to fungal virulence to both hosts. During host infection, only a small subset of genes, including the host-specific EPC effector genes, showed preferential expression on one of the hosts, while gene expression profiles of the majority of other genes, including the five host-nonspecific effector genes, were common to both hosts. This work suggests that C. orbiculare adopts a host-specific effector deployment strategy, in addition to general host-blind virulence mechanisms, for adaptation to cucurbit hosts

Student nurses' understanding about improvement in dietary habit through their practices

看護学生が自己の体験を通じて得た食習慣の改善や患者教育に関する考えを明らかにした。短大看護学科2年生84人を対象に自記式アンケート調査を行い，19歳～21歳の学生73名について分析を行った。栄養学の学習を終えた学生に通常の1日分の栄養摂取量を計算させ，それをもとにそれぞれの食習慣改善計画を立てさせ実行させた。1ヵ月後，再度摂取量の計算をさせて，前回の結果との比較の上で，自分の体験の評価をさせた。その結果，学生が主に考えたことは以下の3点に集約された。①食品の求めやすさや調理の方法の簡単さが食習慣の改善には重要である。②食習慣の改善が困難となるのは，知識の不足や意志の持続性と関連することである。③食習慣の改善の動機づけになるのは，そのことの意義を知ったり，自分の栄養摂取量を点検することである。学生は，食習慣の改善の困難さや容易さおよび患者の栄養指導における留意点について理解していた。Self-administrative questionnaire surveys were conducted twice for 84 junior college students in 1997 and data of 73 students aged 19 to 21 years old obtained were analyzed. Students who had already learned basic dietetics were asked to calculate by themselves one-day nutritional intake, to plan how to improve their dietary habit following their data calculated and to practice those plans. One month later, they calculated the daily intake again and compared it to previous data, and described the results of their practices. Results were as follows ; 1. Easiness of purchasing materials and preparing foods is a key to improve dietary habits readily. 2. A lack of knowledge in nutrition and/or discontinuous intention are bottlenecks in improving the dietary habit. 3. For successful improvement of dietary habit, they must be motivated by the explanation of the significance of dietary improvements, self-monitoring of nutritional states. These results suggested that through this practical study, students could learn not only what things were easy and difficult in improving the dietary habits, but also what they should pay attention to in improving the dietary habit and in orienting other person's nutritional improvement

Development of Full-Length cDNAs from Chinese Cabbage (Brassica rapa Subsp. pekinensis) and Identification of Marker Genes for Defence Response

Arabidopsis belongs to the Brassicaceae family and plays an important role as a model plant for which researchers have developed fine-tuned genome resources. Genome sequencing projects have been initiated for other members of the Brassicaceae family. Among these projects, research on Chinese cabbage (Brassica rapa subsp. pekinensis) started early because of strong interest in this species. Here, we report the development of a library of Chinese cabbage full-length cDNA clones, the RIKEN BRC B. rapa full-length cDNA (BBRAF) resource, to accelerate research on Brassica species. We sequenced 10 000 BBRAF clones and confirmed 5476 independent clones. Most of these cDNAs showed high homology to Arabidopsis genes, but we also obtained more than 200 cDNA clones that lacked any sequence homology to Arabidopsis genes. We also successfully identified several possible candidate marker genes for plant defence responses from our analysis of the expression of the Brassica counterparts of Arabidopsis marker genes in response to salicylic acid and jasmonic acid. We compared gene expression of these markers in several Chinese cabbage cultivars. Our BBRAF cDNA resource will be publicly available from the RIKEN Bioresource Center and will help researchers to transfer Arabidopsis-related knowledge to Brassica crops