Bulletin of British earthquakes 2015

"To our knowledge, there are no studies about the structure and ecological function of extrafloral nectaries (EFNs) in Opuntia robusta. This is the first description of EFNs in O. robusta, where young spines have an interesting structure and a secreting function, which are different from EFNs described in other Cactaceae species. We used light, scanning-electron, and transmission-electron microscopy to examine morphology, anatomy, and ultrastructure of the secretory spines in areoles in female and hermaphrodite individuals of O. robusta. Young cladodes develop areoles with modified and secretory spines as EFNs only active during the early growth phase. EFNs are non-vascularized structures, with no stomata, that consist of a basal meristematic tissue, a middle elongation region, and an apical secretory cone formed by large globular epidermal cells, containing nectar and medullar elongated cells. We observed the presence of Golgi apparatus, vesicles and plastids in the medullar and sup-epidermal cells of the spine. We propose that the nectar is stored in the globular cells at the apex of the spine and secreted by breaking through the globular cells or by pores. We recorded a more frequent presence of ants on younger cladode sprouts producing young secreting spines: this result is parallel with the predictions of Optimal Defense Hypothesis, which states that younger plant organs should be better defended than older ones because their loss produces a higher fitness impairment. Although Diaz-Castelazo’s hypothesis states that a more complex structure of EFNs correlates with their lower among-organs dispersion, comparing to less complex EFNs, non-vascularized structure of EFNs in O. robusta is not associated with their higher among-organs dispersion likened to O. stricta, which produces vascularized EFNs. We provide evidence that this characteristic is not a good taxonomic feature of Opuntia genus. Moreover, the comparison of EFNs of O. robusta and O. stricta suggests that the hypothesis of Diaz-Castelazo should be revised: it is rather a rule but not a law.

The transcriptional regulator JAZ8 interacts with the C2 protein from geminiviruses and limits the geminiviral infection in Arabidopsis

Jasmonates (JAs) are phytohormones that finely regulate critical biological processes, including plant development and defense. JASMONATE ZIM-DOMAIN (JAZ) proteins are crucial transcriptional regulators that keep JA-responsive genes in a repressed state. In the presence of JA-Ile, JAZ repressors are ubiquitinated and targeted for degradation by the ubiquitin/proteasome system, allowing the activation of downstream transcription factors and, consequently, the induction of JA-responsive genes. A growing body of evidence has shown that JA signalling is crucial in defending against plant viruses and their insect vectors. Here, we describe the interaction of C2 proteins from two tomato-infecting geminiviruses from the genus Begomovirus, tomato yellow leaf curl virus (TYLCV) and tomato yellow curl Sardinia virus (TYLCSaV), with the transcriptional repressor JAZ8 from Arabidopsis thaliana and its closest orthologue in tomato, SlJAZ9. Both JAZ and C2 proteins colocalize in the nucleus, forming discrete nuclear speckles. Overexpression of JAZ8 did not lead to altered responses to TYLCV infection in Arabidopsis; however, knock-down of JAZ8 favours geminiviral infection. Low levels of JAZ8 likely affect the viral infection specifically, since JAZ8-silenced plants do not display obvious developmental phenotypes nor present differences in their interaction with the viral insect vector. In summary, our results show that the geminivirus-encoded C2 interacts with JAZ8 in the nucleus, and suggest that this plant protein exerts an anti-geminiviral effect.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The transcriptional regulator JAZ8 interactswith the C2 protein from geminivirusesand limits the geminiviral infection in Arabidopsis

Jasmonates (JAs) are phytohormones that finely regulate critical biological processes, including plant development and defense. JASMONATE ZIM-DOMAIN (JAZ) proteins are crucial transcriptional regulators that keep JA-responsive genes in a repressed state. In the presence of JA-Ile, JAZ repressors are ubiquitinated and targeted for degradation by the ubiquitin/proteasome system, allowing the activation of downstream transcription factors and, consequently, the induction of JA-responsive genes. A growing body of evidence has shown that JA signaling is crucial in defending against plant viruses and their insect vectors. Here, we describe the interaction of C2 proteins from two tomato-infecting geminiviruses from the genus Begomovirus, tomato yellow leaf curl virus (TYLCV) and tomato yellow curl Sardinia virus (TYLCSaV), with the transcriptional repressor JAZ8 from Arabidopsis thaliana and its closest orthologue in tomato, SlJAZ9. Both JAZ and C2 proteins colocalize in the nucleus, forming discrete nuclear speckles. Overexpression of JAZ8 did not lead to altered responses to TYLCV infection in Arabidopsis; however, knock-down of JAZ8 favors geminiviral infection. Low levels of JAZ8 likely affect the viral infection specifically, since JAZ8-silenced plants neither display obvious developmental phenotypes nor present differences in their interaction with the viral insect vector. In summary, our results show that the geminivirus-encoded C2 interacts with JAZ8 in the nucleus, and suggest that this plant protein exerts an anti-geminiviral effect.This work was supported by the Spanish Ministerio de Ciencia y Tecnología (PID2019-107657RB-C22) (ER-B), FEDER program (UMA20-FEDERJA-021) (AG-C), the Shanghai Center for Plant Stress Biology, the Chinese Academy of Sciences, and the Federal Ministry of Education and Research (BMBF) and the Baden-Württemberg Ministry of Science as part of the Excellence Strategy of the German Federal and State Governments (RL-D). TR-D was supported by a President's International Fellowship Initiative (PIFI) postdoctoral fellowship (No. 2016PB042) from the Chinese Academy of Sciences, the “Programa Juan de la Cierva” (IJCI-2017-33367) from the MCIN and FEDER program UMA20-FEDERJA-132 by AEI and by “ERDF A way of making Europe,” by the “European Union.” Funding for Open Access charge: Universidad de Málaga / CBUA

Diez meses de análisis de las enfermedades en especímenes silvestres de Litopenaeus setiferus en el Sur del Golfo de México

The development of shrimp aquaculture in Mexican coasts of the Gulf of Mexico began to be explored using the Pacific white shrimp Litopenaeus vannamei in the mid 90´s. Many concerns over the risk of disease transmission to the economically important native penaeids, have been the main deterrent for the aquaculture of L. vannamei in the region. Concurrently, more than 10 years of research experience on the aquaculture suitability of the native Litopenaeus setiferus from the Terminos Lagoon, in the Yucatán Peninsula, have been accumulated. The aim of this study was then to determine the seasonal variations of the naturally acquired diseases and the possible detection of exotic pathogens. For this, random subsamples (n~60) of juveniles L. setiferus were collected from monthly captures. In order to detect the widest range of pathogens, including infectious hypodermal and hematopoietic necrosis (IHHNV) and white spot syndrome (WSSV) viruses, both histopathological and molecular methods were employed. Monthly prevalence (%) was calculated for every finding. We were able to detect a total of 16 distinct histological anomalies, most of which the presumptive aetiological agent was readily identified. PCR results for viruses were negative. For some pathogens and symbionts, the prevalence was significantly different between the adult and juvenile populations. Prevalence of diseases tended to be higher in juvenile shrimp than in adults. The results of this study indicated that L. setiferus carry a wide variety of pathogens and symbionts that seem to be endemic to penaeids of the Gulf of Mexico, and those juveniles were more conspicuous to acquire pathogens and symbionts than adults.Durante la década de los 90´s se introdujo el camarón blanco del Pacífico Litopenaeus vannamei a los Estados costeros mexicanos del Golfo de México con fines acuícolas, por lo que desde entonces existe preocupación por la posible introducción de enfermedades que puedan afectar a las poblaciones de camarones nativos. La investigación sobre la domesticación de especies nativas para una acuacultura sustentable se ha realizado por más de 10 años, sin embargo, aún existe escasa información sobre las enfermedades que se presentan de manera natural en estas poblaciones y posible trasfaunación. El presente estudio aborda el problema de las enfermedades encontradas en subpoblaciones de jóvenes y adultos de Litopenaeus setiferus del Área natural protegida Laguna de Términos, estado de Campeche, México. Técnicas de histología y biología molecular fueron utilizadas como herramientas de diagnóstico. Se encontró que L. setiferus es portador de patógenos y simbiontes endémicos del Golfo de México, y comparativamente, los jóvenes son más susceptibles en adquirir estas infecciones que los adultos, como probable respuesta al ambiente lacustre que ocupan. No se encontró evidencia de los virus IHHNV y WSSV, aunque en trabajos más recientes en algunos Estados del Norte ya se han detectado en poblaciones silvestres

A ten-month diseases survey on wild Litopenaeus setiferus (Decapoda: Penaeidae) from Southern Gulf of Mexico

The development of shrimp aquaculture in Mexican coasts of the Gulf of Mexico began to be explored using the Pacific white shrimp Litopenaeus vannamei in the mid 90´s. Many concerns over the risk of disease transmission to the economically important native penaeids, have been the main deterrent for the aquaculture of L. vannamei in the region. Concurrently, more than 10 years of research experience on the aquaculture suitability of the native Litopenaeus setiferus from the Terminos Lagoon, in the Yucatán Peninsula, have been accumulated. The aim of this study was then to determine the seasonal variations of the naturally acquired diseases and the possible detection of exotic pathogens. For this, random subsamples (n~60) of juveniles L. setiferus were collected from monthly captures. In order to detect the widest range of pathogens, including infectious hypodermal and hematopoietic necrosis (IHHNv) and white spot syndrome (WSSv) viruses, both histopathological and molecular methods were employed. Monthly prevalence (%) was calculated for every finding. We were able to detect a total of 16 distinct histological anomalies, most of which the presump- tive aetiological agent was readily identified. PCR results for viruses were negative. For some pathogens and symbionts, the prevalence was significantly different between the adult and juvenile populations. Prevalence of diseases tended to be higher in juvenile shrimp than in adults. The results of this study indicated that L. setiferus carry a wide variety of pathogens and symbionts that seem to be endemic to penaeids of the Gulf of Mexico, and those juveniles were more conspicuous to acquire pathogens and symbionts than adults

The effect of sprout length, width, and thickness, air humidity and temperature; on ant number on sprout, during 1 min observation.

<p>The effect of sprout length, width, and thickness, air humidity and temperature; on ant number on sprout, during 1 min observation.</p

Ultrastructure of extrafloral nectary spine.

<p>(A) Basal cell; (B) Detail of a basal cell showing active endoplasmic reticulum and mitochondria; (C) Middle elongated cells showing some vacuoles and numerous pits (arrows); (D) Detail of middle cells showing abundant Golgi apparatus forming vesicles; (E) Internal cell close to the apical secreting cone showing abundant vesicles and mitochondria; (F) Sub epidermal cell, showing vesicle transport between cells by exocytosis and endocytosis; (G) Epidermal cell below the apical secreting cone; with large vacuoles and numerous pits; (H) Epidermal cell of apical secreting cone (nectar reservoirs) showing cuticle and conspicuous pits (arrows), and external granulose material (nectar). cu—cuticle; cw—cell wall; ex—exocytosis; en—endocytosis; ga—Golgi apparatus; er—endoplasmic reticulum; m—mitochondria; va—vacuole; arrows indicate pits at the cell wall. (A) and (E)–bar = 2.0 μm; (B) and (D)–bar = 0.5 μm; (C) and (G)–bar = 5.0 μm; (H) bar = 1 μm.</p

Anatomy of the secreting spine (EFN) of <i>Opuntia robusta</i>.

<p>(A) Whole spine showing three structural regions (asc, mer, bme); (B) Basal meristem (bme) and areolar tissue beneath the spine base: black arrows indicate crystals; (C) Middle elongation region (mer); (D) apical secreting cone (asc); (E) Trichomes surrounding the EFN; (F) Xylem (xy) and phloem (phl) located beneath the spine base; (G) Aniline blue and epifluorescence of phloem: red arrows indicate fluorescence of callose at the plate of sieve elements (filter excitation BP 365 nm and emission LP 397 nm); in—internal tissue, ep—epidermis, tr—trichomes,. (A), (B), (C)–bar = 100 μm; (D) (E), (F), (G)–bar = 50 μm.</p

Areole of young cladode of Opuntia robusta.

<p>(A) Young areola with extrafloral nectary (efn, arrow) behind a persistent leaf, showing a drop of nectar (close up at the corner); (B) Ant collecting nectar from the extrafloral nectary; (C) and (D) Extrafloral nectary is a modified spine with an apical secretory cone (asc); (E) Distribution of the areola components and diagram. asc–apical secretory cone; efn: extrafloral nectary; lf—leaf; s—lateral spines; sp—central spine; tr—trichomes. (A) and (B)–bar = 2 mm, (C) and (D)–bar = 1mm, (E)–bar = 3 mm.</p

Scanning Electron Micrograph of extrafloral nectary spine.

<p>(A) Whole modified spine; (B) Transition region between middle and apical secreting cone showing intercellular spaces and a broken cell; (C) Apical secreting cone; (D) Detail of the apex. asc—apical secreting cone; efn—extrafloral nectary; tr—trichome. (A)—(C)—hermaphrodite, (D)–feminine.</p