First Report of "Candidatus Liberibacter solanacearum" in Pepper Plants in México.

Bell pepper (Capsicum annuum) plants exhibiting symptoms that resembled those of potato psyllid (Bactericera cockerelli Sulc) damage and "Candidatus Liberibacter solanacearum" infection (2) were observed in a pepper field in La Cruz de Elota, Sinaloa, México in March 2009, with an infection rate of 1.5%. Plants exhibited chlorotic or pale green apical growth and leaf cupping, sharp tapering of the leaf apex, shortened internodes, and an overall stunting (2). Total DNA was extracted from the top whole leaf tissue of nine symptomatic and five asymptomatic pepper plants with cetyltrimethylammoniumbromide (CTAB) buffer (3,4). Seven and eight of the nine selected symptomatic pepper plants yielded the expected 1,168-bp 16S rDNA and the expected 669-bp rplJ/rplL ribosomal protein gene amplicons with the "Ca. L. solanacearum" specific OA2/OI2c and CL514F/CL514R primer pairs, respectively, indicating the presence of liberibacter (2,4). Nucleic acid from asymptomatic pepper plants yielded no products with these primers. Three amplicons generated from symptomatic pepper plants with each primer pair were cloned into pCRII-TOPO plasmid vectors (Invitrogen, Carlsbad, CA) and three clones of each amplicon were sequenced in both directions (ACGT, Inc., Wheeling, IL). BLAST analysis of the 16S rDNA consensus sequence (GenBank Accession No. FJ957896) showed 100% identity to 16S rDNA sequences of "Ca. L. solanacearum" amplified from Solanum betaceum (EU935004) and S. lycopersicum (EU834130) from New Zealand (2), and "Ca. L. psyllaurous" from potato psyllids (EU812559) (1). The ribosomal protein gene consensus sequence (GenBank Accession No. FJ957894) was 100% identical to the analogous rplJ and rplL "Ca. L. solanacearum" ribosomal protein gene sequence amplified from S. lycopersicum (EU834131) from New Zealand (2) and to 'Ca. Liberibacter' sp. sequence amplified from zebra chip-infected potato tubers from Lancaster, CA (FJ498803). To our knowledge, this is the first report of "Ca. L. solanacearum" associated with bell pepper in México. "Ca. L. solanacearum" was first reported in tomato and pepper plants in 2008 in New Zealand, where it has resulted in plant decline and significant yield loss, resulting in millions of dollars in losses to the commercial glasshouse tomato and pepper industry (2). Zebra chip, a new and emerging potato disease associated with 'Ca. Liberibacter' sp., was first identified in México in 1994, where it has caused significant economic damage, often leading to abandonment of entire potato fields (3,4). References: (1) A. K. Hansen et al. Appl. Environ. Microbiol. 74:5862, 2008. (2) L. W. Liefting et al. Plant Dis. 93:208, 2009. (3) J. E. Munyaneza et al. J. Econ. Entomol. 100:656, 2007. (4) J. E. Munyaneza et al. Plant Dis. 93:552, 2009.

First Report of "Candidatus Liberibacter solanacearum" in Tomato Plants in México.

Tomato (Solanum lycopersicum) plants exhibiting symptoms resembling those of permanent yellowing disease (known in Mexico as "permanente del tomate") that is commonly associated with phytoplasmas (1) were observed in tomato fields in Sinaloa, México in March 2009. Plant symptoms also resembled those caused by "Candidatus Liberibacter solanacearum" infection (2). Affected plants showed an overall chlorosis, severe stunting, leaf cupping, purple discoloration of veins, excessive branching of axillary shoots, and leaf scorching (1,2). Symptom incidence ranged from 18 to 40%. To investigate whether liberibacter is associated with permanent yellowing disease of tomato in México, eight symptomatic and five asymptomatic tomato plants were collected from two fields in La Cruz de Elota and Culiacán, Sinaloa. Total DNA was extracted from the top whole leaf tissue of symptomatic and asymptomatic plants with cetyltrimethylammoniumbromide (CTAB) buffer (3,4). DNA samples were tested by PCR using primer pairs OA2/OI2c and CL514F/CL514R, which amplify a sequence from the 16S rDNA and rplJ and rplL ribosomal protein genes, respectively, of "Ca. L. solanacearum" (2,4). The DNA samples were also tested for phytoplasmas with nested PCR using universal primer pairs P1/P7 and fU5/rU3 (3). DNA from five and four symptomatic plants yielded the expected 1,168-bp 16S rDNA and 669-bp rplJ/rplL amplicons, respectively, indicating the presence of liberibacter. Extracts from asymptomatic plants yielded no products with these primers. Amplicons generated from three symptomatic plants with each primer pair were cloned into pCRII-TOPO plasmid vectors (Invitrogen, Carlsbad, CA) and three clones of each of these amplicons were subsequently sequenced in both directions (ACGT, Inc., Wheeling, IL). BLAST analysis of the 16S rDNA consensus sequence (GenBank Accession No. FJ957897) showed 100% identity to 16S rDNA sequences of "Ca. L. solanacearum" amplified from S. betaceum (EU935004) and S. lycopersicum (EU834130) from New Zealand (2), and "Ca. L. psyllaurous" from potato psyllids (EU812559). The rplJ/rplL consensus sequence (GenBank Accession No. FJ957895) was 100% identical to the analogous rplJ and rplL "Ca. L. solanacearum" ribosomal protein gene sequence amplified from S. lycopersicum (EU834131) from New Zealand (2) and 'Ca. Liberibacter' sp. sequence amplified from zebra chip-infected potatoes from Lancaster, CA (FJ498803). No phytoplasmas were detected in the symptomatic tomato plants. To our knowledge, this is the first report of "Ca. L. solanacearum" associated with tomatoes in México. In 2008, this bacterium was detected in glasshouse tomatoes in New Zealand and caused millions of dollars in losses to the commercial glasshouse tomato industry (2). References: (1) R. L. Holguín-Peña et al. Plant Dis. 91:328, 2007. (2) L. W. Liefting et al. Plant Dis. 93:208, 2009. (3) J. E. Munyaneza et al. J. Econ. Entomol. 100:656, 2007. (4) J. E. Munyaneza et al. Plant Dis. 93:552, 2009.

Nutritional properties of quality protein maize and chickpea extruded based weaning food.

Malnutrition is one of the major causes of morbidity and mortality among young children in most of the developing countries. To minimize the adversities of malnutrition, low-cost infant supplementary foods have been developed and are being supplied to the needy through state-sponsored nutrition intervention programmers. The present study had two objectives: to determine the best combination of nixtamalized extruded quality protein maize (NEMF) and extruded chickpea (ECF) flours for producing a weaning food, and to evaluate the nutritional properties of the optimized NEMF/ECF mixture and the weaning food. The NEMF and ECF were produced applying combinations of extrusion temperature/screw speed of 79.4 degrees C/73.5 rpm, and 150.5 degrees C/190.5 rpm, respectively. Response surface methodology was applied to determine the optimum combination NEMF/ECF; the experimental design generated 11 assays. Mixtures from each assay were evaluated for true protein (TP) and available lysine (AL). Each one of 11 mixtures were used for preparing 11 weaning foods which were sensory evaluated for acceptability (A). The best combination of NEMF/ECF for producing a weaning food was NEMF = 21.2%/ ECF = 78.8 %. This mixture had a global desirability (D) of 0.93; it contained 20.07% proteins (DM), 5.70% lipids (DM), and 71.14% carbohydrates (DM); its essential amino acids (EAA) profile satisfactorily covered the EAA requirements for children 2-5 years old, except for Trp. The weaning food prepared with the optimized mixture had high protein quality and digestibility and could be used to support the growth of infants.

Infant food from quality protein maize and chickpea: optimization for preparing and nutritional properties.

The present study had two objectives: to determine the best combination of nixtamalized maize flour (NMF) from quality protein maize and extruded chickpea flour (ECF) for producing an infant food, and to evaluate the nutritional properties of the optimized NMF/ECF mixture and the infant food. Response surface methodology (RSM) was applied to determine the best combination of NMF/ECF; the experimental design (Lattice simplex) generated 11 assays. Mixtures from each assay were evaluated for true protein and available lysine. Each one of 11 mixtures was used for preparing 11 infant foods that were sensory evaluated for acceptability. A common optimum value for the three response variables was obtained utilizing the desirability method. The best combination of NMF/ECF for producing an infant food was NMF = 26.7%/ECF = 73.3%; this optimized mixture had a global desirability of 0.87; it contained 19.72% dry matter (DM) proteins, 6.10% (DM) lipids, 71.45% (DM) carbohydrates, and 2.83% (DM) minerals; its essential amino acids profile covered the amino acids requirements for children 10-12 years old. The infant food prepared from optimized mixture had an in vitro protein digestibility of 87.9%, and a calculated protein efficiency ratio of 1.86. Infant food could be used to support the growth of infants in developing countries.