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- Viral diagnosis in cultivars of Ipomoea batatas (L.) LamPublication . Andrade, Carlos G.; Silva, Emanuel M. da; Ragonezi, Carla; Carvalho, Miguel Â. A. Pinheiro deIpomoea batatas (L.) Lam. commonly known as sweet potato, is an important staple food worldwide, mainly due to its high nutritional value and yield. However, vegetative reproduction of sweet potato makes it more susceptible to viral infections, which threatens its productivity, quality, and difficult long-term preservation in germplasm banks. Also, it can act as a virus reservoir infecting the rest of the plant accessions in the bank collections. Hence, this work aimed to screen Begomovirus, Potyvirus, and Carlavirus infections in 16 traditional sweet potato cultivars from the germplasm collection of the ISOPlexis Germplasm Bank, Madeira, Portugal. The infection prevalence by these viruses among cultivars was 81.25%, 25.00%, and 6.25%, respectively; being ISOP1011 the only accession coinfected by Potyvirus and Carlavirus. The accessions ISOP1006, ISOP1010, and ISOP1047 were also coinfected by Begomovirus and Potyvirus, highlighting their vulnerability to viral infections. The ISOP1005 and ISOP1027 accessions were the only ones not infected by any of these viruses. The analysis of the partial sequence obtained from the Carlavirus detected in the accession ISOP1011, revealed the existence of an ORF that encodes for 93 amino acids of the catalytic domain of an RNA-directed RNA polymerase related to the Tymovirus protein family, as could be confirmed by comparison with proteins stored in UniProtKB. Multiple sequence alignment with these proteins showed that Motifs A and B of the catalytic domain were conserved. The search for sequence similarity with sequences deposited in GenBank reported a high sequence identity with Sweet potato yellow mottle virus (SPYMV) and Sweet potato chlorotic fleck virus (SPCFV). However, the 9-11% discrepancy in nucleotide sequence identity and a phylogenetic analysis carried out using the maximum probability method suggests the virus isolated from ISOP1011 is a new divergent strain of the SPCFV species.
- Phenotyping the ideotypes of two maize landraces from Madeira archipelago using morpho-agronomic traits and zein patternPublication . Carvalho, Miguel Â. A. Pinheiro de; Sardinha, Carmen M. S.; Gouveia, Carla S.S.; Silva, Emanuel M. da; Nóbrega, Humberto G. M.; Ganança, José F. T.; Nóbrega, Sónia R.; Santos, Teresa M. M. dosMadeira Archipelago holds specific maize genetic resources whose populations, representing field diversity, were previously classified into four main landrace groups. The ISOPs 0061 and 0070, with common names of “Milho Sequeiro” and “Milho Branco” yellow and white maize, respectively, represent the ideotypes of two of these landraces. These ideotypes have now been analyzed using morpho-agronomic and biochemical traits, to phenotype these landraces. The variation of nine of the ten morpho-agronomic traits was used to separate the landraces ideotypes. However, the seven traits of seed biochemical composition did not allow to segregate the landraces ideotypes. This is not the case of zein pattern, which polymorphism shows to be specific for each ideotype. The original ideotypes populations were regenerated twice under low input conditions. Zein patterns of the original and regenerated accessions were compared, using two electrophoresis techniques. The lab-on-a-chip electrophoresis showed that the standard SDS-PAGE zein pattern with six fractions could be separated into eighteen (ISOP 0061) and twenty (ISOP 0070) protein bands. In contrast, no significant changes were detected in the zein pattern structure of the initial and regenerated accessions of both landraces ideotypes. The chip electrophoresis showed to be a suitable technique to screen and characterize a large number of individuals and accessions of the germplasm collections, due to its reproducibility. In particular, the zein patterns can be used to phenotype ideotypes and establish a formula representing their structure, allowing to detect changes in landrace structure, occurring as a result of gene bank management actions.
- Evidences of organic acids exudation in aluminium stress responses of two Madeiran wheat (Triticum aestivum L.) landracesPublication . Rodrigues, Marta; Ganança, José F.T.; Silva, Emanuel M. da; Santos, Teresa M. M. dos; Slaski, Jan J.; Zimny, Janusz; Carvalho, Miguel Â. A. Pinheiro deTwo wheat (Triticum aestivum L.) Madeiran landraces were subjected to 100 μM and 200 μM of aluminium (Al) in hydroponic culture, assessing the organic acid exudation role in plant’s responses to this metal. Samples of initial landrace populations (F0), F3 and haplodiploid lines (DH) were evaluated using standard tests: eriochrome cyanine R staining, root elongation and callose accumulation in roots. Root exudates were obtained to determine if the accumulation of malic and citric acids in hydroponic medium was a response to Al exposure. Additionally, the presence of ALMT1 gene was determined using five microsatellite markers. Standard tests confirmed that ISOP 76 was Al tolerant and ISOP 239, Al susceptible. ISOP 76, in the presence of 100 μM Al, exuded substantially more malic acid (12.87 to 43.33 mg/L), than ISOP 239 (3.65 to 7.72 mg/L). The levels of both organic acid exudation were substantially lower in ISOP 239 than in the ISOP 76. In the presence of 200 μM Al, ISOP 76 F0 shows a higher root elongation ratio (better tolerates Al), but the DH line was the one that exuded higher content of malic acid. Different gene alleles and promoters were detected in both landraces. Molecular differences could explain the observed dissimilarity in organic acid exudation response to Al stress.