Emergent Protective Organogenesis in Date Palms: A Morpho-Devo-Dynamic Adaptive Strategy during Early Development.

Desert plants have developed mechanisms for adapting to hostile desert conditions, yet these mechanisms remain poorly understood. Here, we describe two unique modes used by desert date palms (Phoenix dactylifera) to protect their meristematic tissues during early organogenesis. We used x-ray micro-computed tomography combined with high-resolution tissue imaging to reveal that, after germination, development of the embryo pauses while it remains inside a dividing and growing cotyledonary petiole. Transcriptomic and hormone analyses show that this developmental arrest is associated with the low expression of development-related genes and accumulation of hormones that promote dormancy and confer resistance to stress. Furthermore, organ-specific cell-type mapping demonstrates that organogenesis occurs inside the cotyledonary petiole, with identifiable root and shoot meristems and their respective stem cells. The plant body emerges from the surrounding tissues with developed leaves and a complex root system that maximizes efficient nutrient and water uptake. We further show that, similar to its role in Arabidopsis (Arabidopsis thaliana), the SHORT-ROOT homolog from date palms functions in maintaining stem cell activity and promoting formative divisions in the root ground tissue. Our findings provide insight into developmental programs that confer adaptive advantages in desert plants that thrive in hostile habitats.

Correction to: Evaluation of the presence of Paenibacillus larvae in commercial bee pollen using PCR amplification of the gene for tRNACys.

In the article mentioned above an author's name was misspelled.

Evaluation of the presence of Paenibacillus larvae in commercial bee pollen using PCR amplification of the gene for tRNACys.

American foulbrood (AFB) caused by Paenibacillus larvae is the most destructive honeybee bacterial disease and its dissemination via commercial bee pollen is an important mechanism for the spread of this bacterium. Because Mexico imports bee pollen from several countries, we developed a tRNACys-PCR strategy and complemented that strategy with MALDI-TOF MS and amplicon-16S rRNA gene analysis to evaluate the presence of P. larvae in pollen samples. P. larvae was not detected when the tRNACys-PCR approach was applied to spore-forming bacterial colonies obtained from three different locations and this result was validated by bacterial identification via MALDI-TOF MS. The genera identified in the latter analysis were Bacillus (fourteen species) and Paenibacillus (six) species. However, amplicon-16S rRNA gene analysis for taxonomic composition revealed a low presence of Paenibacillaceae with 0.3 to 16.2% of relative abundance in the commercial pollen samples analyzed. Within this family, P. larvae accounted for 0.01% of the bacterial species present in one sample. Our results indicate that the tRNACys-PCR, combined with other molecular tools, will be a useful approach for identifying P. larvae in pollen samples and will assist in controlling the spread of the pathogen.

pMEX01, a 70kb Plasmid Isolated From Escherichia Coli That Confers Resistance to Multiple ß-Lactam Antibiotics

Abstract Multidrug-resistant microorganisms are of great concern to public health. Genetic mobile elements, such as plasmids, are among the most relevant mechanisms by which bacteria achieve this resistance. We obtained an Escherichia coli strain CM6, isolated from cattle presenting severe diarrheic symptoms in the State of Querétaro, Mexico. It was found to contain a 70 kb plasmid (pMEX01) with a high similarity to the pHK01-like plasmids that were previously identified and described in Hong Kong. Analysis of the pMEX01 sequence revealed the presence of a blaCTX-M-14 gene, which is responsible for conferring resistance to multiple β-lactam antibiotics. Several genes putatively involved in the conjugative transfer were also identified on the plasmid. The strain CM6 is of high epidemiological concern because it not only displays resistance to multiple β-lactam antibiotics but also to other kinds of antibiotics.

pMEX01, a 70kb plasmid isolated from Escherichia coli that confers resistance to multiple ß-lactam antibiotics.

Multidrug-resistant microorganisms are of great concern to public health. Genetic mobile elements, such as plasmids, are among the most relevant mechanisms by which bacteria achieve this resistance. We obtained an Escherichia coli strain CM6, isolated from cattle presenting severe diarrheic symptoms in the State of Querétaro, Mexico. It was found to contain a 70kb plasmid (pMEX01) with a high similarity to the pHK01-like plasmids that were previously identified and described in Hong Kong. Analysis of the pMEX01 sequence revealed the presence of a blaCTX-M-14 gene, which is responsible for conferring resistance to multiple ß-lactam antibiotics. Several genes putatively involved in the conjugative transfer were also identified on the plasmid. The strain CM6 is of high epidemiological concern because it not only displays resistance to multiple ß-lactam antibiotics but also to other kinds of antibiotics.