Agronomic and digital phenotyping evaluation of sweet sorghum public varieties and F1 hybrids with potential for ethanol production in Spain

12 Pags., 3 Tabls., 3 Figs. The definitive version is available at: http://www.maydica.org/articles/58_042.pdfSweet sorghum is receiving a lot of attention as a potential crop for bioethanol production in the Mediterranean area. Its advantages are a combination of high productivity and good response to abiotic stresses. There is a lack of information on adaptation of sweet sorghum cultivars to Mediterranean conditions. This investigation was undertaken to explore the adaptation and agronomic traits of a group of international varieties of sweet sorghum, to identify the best candidates to initiate a breeding program for this species in Spain. Sixteen varieties, chosen based on passport, evaluation and genetic data from the USDA GRIN database, were sown in 2011 in an irrigated field plot in Zaragoza, Spain. Several agronomic traits, like fresh weight were determined in the field. Juice samples were analyzed for Brix and POL score of the juice of the stalks. Some of the varieties, particularly Sugar Drip, MN2826, Smith, Ramada and Dale, offer good prospects to initiate a breeding program for Spanish conditions, due to a combination of good agronomics, high sugar content and spread of flowering dates. At the same time, these varieties were used as pollinators to produce hybrids in crosses with either sweet A-lines or grain sorghum populations. The potential to use F1 hybrids in this species was explored by analysing the growth of five of the most representative F1 hybrids (three F1 sweet sorghum hybrids and two crosses of grain sorghum by sweet sorghum) and their parents through a digital phenotyping analysis. Plant size was monitored on a daily basis. The sweet sorghum varieties apparently revealed different heterotic behaviour when crossed to sweet or grain female parents. Mid-parent heterosis for plant growth was detected, but suffered variations over time, which may be related to the experimental system.This study was supported by Plan E I+D project ‘Realización del subproyecto sorgosweet. Producción y desarrollo de cultivos energéticos no alimentarios’ 2010, funded by the Ministry of Science and Innovation, led by Abengoa Bioenergía.Peer Reviewe

A Temporary Immersion System to Improve Cannabis sativa Micropropagation

The aim of this study was to propagate axillary shoots of Cannabis sativa L. using liquid medium in temporary immersion bioreactors. The effect of immersion frequency (3 or 6 immersions per day), explant type (apical or basal sections), explant number (8, 10, and 16 explants), mineral medium (Murashige and Skoog half-strength nitrates, β-A and β-H, all supplemented with 2-μM metatopoline), sucrose supplementation (2, 0.5, and 0% sucrose), culture duration (4 and 6 weeks), and bioreactor type (RITA® and Plantform™) were investigated. As a result, we propose a protocol for the proliferation of cannabis apical segments in RITA® or Plantform™ bioreactors. The explants (8 per RITA® and 24 per Plantform™) are immersed for 1 min, 3 times per day in β-A medium supplemented with 2-μM metatopoline and 0.5% of sucrose and subcultured every 4 weeks. This is the first study using temporary immersion systems in C. sativa production, and our results provide new opportunities for the mass propagation of this species.This work was supported by a research contract from Phytoplant Research (Ref. 20190548) and by the Xunta de Galicia (Spain) through the projects IN607A 2021/06 and Contrato Programa 2021 (AGI/CSIC I+D+I 2021, Ref- ACAM 20210200033)

Characterization of the galactono-1,4-lactone dehydrogenase from pepper fruits and its modulation in the ascorbate biosynthesis. Role of nitric oxide

Pepper fruit is one of the highest vitamin C sources of plant origin for our diet. In plants, ascorbic acid is mainly synthesized through the L-galactose pathway, being the L-galactono-1,4-lactone dehydrogenase (GalLDH) the last step. Using pepper fruits, the full GalLDH gene was cloned and the protein molecular characterization accomplished. GalLDH protein sequence (586 residues) showed a 37 amino acids signal peptide at the N-terminus, characteristic of mitochondria. The hydrophobic analysis of the mature protein displayed one transmembrane helix comprising 20 amino acids at the N-terminus. By using a polyclonal antibody raised against a GalLDH internal sequence and immunoblotting analysis, a 56 kDa polypeptide cross-reacted with pepper fruit samples. Using leaves, flowers, stems and fruits, the expression of GalLDH by qRT-PCR and the enzyme activity were analyzed, and results indicate that GalLDH is a key player in the physiology of pepper plants, being possibly involved in the processes which undertake the transport of ascorbate among different organs. We also report that an NO (nitric oxide)-enriched atmosphere enhanced ascorbate content in pepper fruits about 40% parallel to increased GalLDH gene expression and enzyme activity. This is the first report on the stimulating effect of NO treatment on the vitamin C concentration in plants. Accordingly, the modulation by NO of GalLDH was addressed. In vitro enzymatic assays of GalLDH were performed in the presence of SIN-1 (peroxynitrite donor) and S-nitrosoglutahione (NO donor). Combined results of in vivo NO treatment and in vitro assays showed that NO provoked the regulation of GalLDH at transcriptional and post-transcriptional levels, but not post-translational modifications through nitration or S-nitrosylation events promoted by reactive nitrogen species (RNS) took place. These results suggest that this modulation point of the ascorbate biosynthesis could be potentially used for biotechnological purposes to increase the vitamin C levels in pepper fruits.This work has been supported by the ERDF-cofinanced grant AGL2015-65104-P from the Ministry of Economy and Competitiveness, Spain. MRR acknowledges an FPI contract (BES-2012-055904) from the Ministry of Economy and Competitiveness, Spain. The quantification of ascorbate levels by HPLC-MS was achieved at the Scientific Instrumentation Service, Estación Experimental del Zaidín, CSIC, Granada, Spain. The technical assistance of Carmelo Ruiz, María Jesús Campos, Beatriz Sánchez-Calvo and Elena Sánchez-Romero is acknowledged.Peer Reviewe

Patrón de expresión del gen ERF1 durante el enraizamiento adventicio y la embriogénesis somática en castaño y roble

Trabajo presentado en la Reunión de Transferencia de Tecnología, celebrada en Aranjuez (España) los días 25 y 26 de enero de 2012Peer reviewe

Gene expression patterns during the acquisition of embryogenic competence and embryo development in Fagaceae species

Trabajo presentado en la 2nd International Conference of the IUFRO WORKING PARTY 2.09.02: Somatic Embryogenesis and Other Vegetative Propagation Tecnhologies, celebrada en Brno (República Checa) del 25 al 28 de junio de 2012Somatic embryogenesis is a powerful method of tree regeneration that potentially offers an efficient system for mass clonal propagation, germplasm conservation and genetic improvement (Vieitez et al. 2012). Somatic embryos develop through a sequence of stages associated with morphological and biochemical changes related to genomic activity. Reprogramming of the current gene expression pattern of differentiated somatic cells is required for cellular dedifferentiation and the acquisition of embryogenic competence of certain responsive cells to allow them to establish new development programmes. This developmental switching involves activation and repression of specific genes that confer on somatic cells the ability to initiate the embryogenic pathway (Chugh and Khurana, 2002). Moreover, the different developmental stages of somatic embryos are also controlled by the temporal expression of specific genes. However, the molecular mechanisms underlying the switch of the somatic cell fate towards embryogenic competence and the regulation of embryo development remain unclear. In our laboratory, somatic embryos have been induced from different types of oak and chestnut material, allowing the establishment of different clonal embryogenic lines which had been maintained by secondary embryogenesis (Corredoira et al. 2003; Toribio et al. 2004; Valladares et al. 2006). The induction system and the different embryogenic lines are highly valuable for studying the molecular events that control the onset and development of somatic embryos. To study the gene expression during somatic embryo histodifferentiation, embryos at the globular, torpedo and cotyledonary stage were collected from proliferating cultures. In addition, leaf explants cultured following the somatic embryo induction procedure were used to examine the gene expression during early stages of somatic embryo initiation. The objective of this study was to analyse the spatio-temporal expression of four genes (SCL1, ERF1, SERK-like and CPE), associated with morphogenetic processes in oak and chestnut, which have been isolated by our research group. Gene expression analysis has been carried out by qPCR and in situ hybridization (Vielba et al. 2011). The SCL1 gene encodes a GRAS family transcription factor (Sanchez et al. 2007), the ERF1 gene belongs to the AP2/ERF family, the SERK-like gene encodes a protein containing characteristics domains of the SERK proteins, and the CPE gene encodes for a glycine rich protein (Gil et al. 2003). In general, we found not fundamental differences in the expression pattern of each gene between chestnut and oak somatic embryos. However, some differences in the gene expression profiles were observed among different embryogenic lines that could be related to their embryogenic potential. The CPE gene was abundantly expressed in very early stages of somatic embryos, being developmentally regulated during somatic embryogenesis. The SCL1 and SERK-like transcripts also accumulated at the highest levels in globular stage somatic embryos, being down-regulated during embryo development. Transcript levels of ERF1 increased during embryo development, and the highest levels were detected in cotyledonary somatic embryos. In situ hybridization experiments revealed the presence of high mRNA levels of QrCPE, QrSCL1, QrSERK-like and QrERF1 in oak proembryogenic structures originated during the induction process. Therefore, these genes seem to be associated with embryo induction in oak. In addition, initial experiments showed that each gene exhibit a distinct tissue-specific expression at different stages of embryo development. Our results indicate that these four genes participate in the induction and development processes of somatic embryos in oak and chestnut. Further experiments are now being carried out in order to better characterize the expression pattern and regulation of these genes and to elucidate their possible role during somatic embryogenesis.This work was funded by the Xunta de Galicia (10MRU00033PR)Peer reviewe

Estudios de expresión génica durante el enraizamiento in vitro y la embriogénesis somática en fagaceas

Trabajo presentado en la Reunión de la Red de genómica y Diversidad genética Forestal (GEN2FOR) (2010), celebrada en Navas del Marqués, Ávila (España), los días 1 y 2 de diciembre de 2010Peer reviewe