Amots Hetzroni

Transcriptional profiling of sweetpotato (Ipomoea batatas) roots indicates down-regulation of lignin biosynthesis and up-regulation of starch biosynthesis at an early stage of storage root formation

BackgroundThe number of fibrous roots that develop into storage roots determines sweetpotato yield. The aim of the present study was to identify the molecular mechanisms involved in the initiation of storage root formation, by performing a detailed transcriptomic analysis of initiating storage roots using next-generation sequencing platforms. A two-step approach was undertaken: (1) generating a database for the sweetpotato root transcriptome using 454-Roche sequencing of a cDNA library created from pooled samples of two root types: fibrous and initiating storage roots; (2) comparing the expression profiles of initiating storage roots and fibrous roots, using the Illumina Genome Analyzer to sequence cDNA libraries of the two root types and map the data onto the root transcriptome database.ResultsUse of the 454-Roche platform generated a total of 524,607 reads, 85.6% of which were clustered into 55,296 contigs that matched 40,278 known genes. The reads, generated by the Illumina Genome Analyzer, were found to map to 31,284 contigs out of the 55,296 contigs serving as the database. A total of 8,353 contigs were found to exhibit differential expression between the two root types (at least 2.5-fold change). The Illumina-based differential expression results were validated for nine putative genes using quantitative real-time PCR. The differential expression profiles indicated down-regulation of classical root functions, such as transport, as well as down-regulation of lignin biosynthesis in initiating storage roots, and up-regulation of carbohydrate metabolism and starch biosynthesis. In addition, data indicated delicate control of regulators of meristematic tissue identity and maintenance, associated with the initiation of storage root formation.ConclusionsThis study adds a valuable resource of sweetpotato root transcript sequences to available data, facilitating the identification of genes of interest. This resource enabled us to identify genes that are involved in the earliest stage of storage root formation, highlighting the reduction in carbon flow toward phenylpropanoid biosynthesis and its delivery into carbohydrate metabolism and starch biosynthesis, as major events involved in storage root initiation. The novel transcripts related to storage root initiation identified in this study provide a starting point for further investigation into the molecular mechanisms underlying this process.

Evaluation of colony losses in Israel in relation to the incidence of pathogens and pests

To evaluate symptoms, extent, and possible causes of colony decline and losses in Israel, we carried out (1) a survey of honeybee colony losses and potential causes via mail and phone; (2) systematic sampling of healthy and problematic beehives after requeening in the winter; (3) detection of Varroa and pathogens including, viruses and Nosema ceranae, by microbiological means and sensitive RT-PCR. From 58 beekeepers (46 000 colonies) interviewed, 40% complained of extensive colony loses during 2008. Examination and sampling for pests and pathogens of 113 hives in the winter of 2009 showed 35% of hives with Nosema and 21% with V. destructor. The most frequent viruses detected were Black Queen Cell Virus, Israeli Acute Paralysis Virus, and Deformed Wing Virus. A significant negative correlation was found between worker population in the hive and the presence of viral and Nosema infections.

Development of an automatic monitoring trap for Mediterranean fruit fly (Ceratitis capitata) to optimize control applications frequency

Abstract Continuous monitoring of population fluctuations is important to improve the control of economic pests. The Mediterranean fruit fly [medfly; Ceratitis capitata (Wiedemann)] is a major economic pest of fruit crops worldwide, particularly in the Middle East. The current medfly weekly monitoring method, manual counting, results in a suboptimal spraying frequency in citrus orchards. This paper describes the development of an automatic trap for sequential medfly remote monitoring. To our knowledge, it is the first automatic trap developed for medfly monitoring. A new cylinder-shaped trap was designed, and optical sensors specifically created for detecting and counting dead or stunted Medflies were embedded in it. Field tests were conducted to estimate the trapping efficiency, accuracy and over-counting of the medfly Automatic Traps (medfly-ATs). medfly-ATs and Steiner traps were placed in commercial citrus orchards over five different periods between the years 2013 and 2015. The medfly-AT and conventional Steiner trap were found to have similar trapping efficiencies under field conditions. The accuracy of the medfly-AT counts ranged between 88% and 100%; the absolute over-counting in all experimental sites and periods was three flies. Over-counting was mostly due to ants and rain. The paper discusses the importance of field tests in evaluating the performance of automatic traps. Results of an informal experiment conducted in a commercial orchard showed that daily monitoring using the medfly-AT device holds promise for reducing insecticide applications, but extensive in-field experiments should be conducted to prove it.

Imaging techniques for chemical application on crops

This paper presents a state-of-the-art review of available image sensing technologies and developments for site-specific application of agricultural chemicals. This includes a review of detection features, sensing technologies, system integration, information systems and prototype operational systems.

Computer Image Analysis to Locate Targets for an Agricultural Robot

A real-time computer vision system has been implemented on a prototype field robotic harvester. Gray-level image processing algorithm and routines have been developed and integrated into a real-time pipeline system to locate melons in the field. 80% of fruits were successfully detected. Preliminary investigation of applying Infra-Red imaging to detect melons was performed.

Developing Spatial Decision Support System for Medfly Control in Israel

The Mediterranean fruit fly (Ceratitis capitata Wiedemann; Medfly) is among the world’s most economically harmful pests. Medfly control in citrus plantations in Israel is centralized. To determine time and space of control, about 2,300 sexual lures, distributed in susceptible regions, are observed by field scouts in intervals of about ten days. The scouts report to three zone coordinators who, in turn, determine the time, space and mode of the control measures (aerial or ground application). Taking into consideration all the relevant parameters is quite impossible for large areas within a short time and most of the rulings are strictly biased. The sprayed areas are larger than necessary with harsher environmental and economical impact. This paper describes the main steps of the development of an initial spatial DSS (SDSS) for Medfly control in Israel aka MedCil, which will assist the coordinators in the decision making procedure. The MedCil is based on the Bayesian rule. Its development and realization involved four main phases: 1. acquisition of expert knowledge related to the spraying decision process by interviews and discussions with the coordinators; 2. identifying the relevant criteria and the definition of a control decision tree; 3. transforming qualitative knowledge into quantitative measures; 4. Combination of the decision tree in a GIS environment and evaluate its performance. The MedCil output is a map that classifies the citrus plots into one of the following: Spraying; Spraying is recommended; Spraying is not recommended; No-spraying; No data. In addition, the MedCil warns on data irregularities, i.e., an empty trap amid an area of high capture rate.

Methoden für die präzise obstbauliche Produktion

Der Ansatz von Precision Horticulture im Obstbau lehnt sich an das aus dem Ackerbau stammende Konzept der Prazisionslandwirtschaft bzw. der teilflachenspezifischen Bewirtschaftung an. Hierbei sollen prazise an das individuelle Geholzwachstum angepasste Pflegemasnahmen die bislang praktizierte einheitliche Behandlung aller Baume in einer Anlage ablosen. Voraussetzungen hierfur sind u. a. Bodenkarten und Informationen zum Pflanzenwachstum. Das Ziel ist es, den informationsgestutzten Obstbau voranzutreiben und durch ein raumlich und zeitlich differenziertes Management eine effizientere und nachhaltigere Bewirtschaftung zu erreichen.