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Abstract Elevated nighttime temperatures resulting from climate change significantly impact the rice crop worldwide. The rice (Oryza sativa L.) plant is highly sensitive to high nighttime temperature (HNT) during grain-filling (reproductive stage). HNT stress negatively affects grain quality traits and has a major impact on the value of the harvested rice crop. In addition, along with grain dimensions determining rice grain market classes, the grain appearance and quality traits determine the rice grain market value. During the last few years, there has been a major concern for rice growers and the rice industry over the prevalence of rice grains opacity and the reduction of grain dimensions affected by HNT stress. Hence, the improvement of heat-stress tolerance to maintain grain quality of the rice crop under HNT stress will bolster future rice value in the market. In this study, 185 F 12 -recombinant inbred lines (RILs) derived from two US rice cultivars, Cypress (HNT-tolerant) and LaGrue (HNT-sensitive) were screened for the grain quality traits grain length (GL), grain width (GW), and percent chalkiness (%chalk) under control and HNT stress conditions and evaluated to identify the genomic regions associated with the grain quality traits. In total, there were 15 QTLs identified; 6 QTLs represented under control condition explaining 3.33% to 8.27% of the phenotypic variation, with additive effects ranging from − 0.99 to 0.0267 on six chromosomes and 9 QTLs represented under HNT stress elucidating 6.39 to 51.53% of the phenotypic variation, with additive effects ranging from − 8.8 to 0.028 on nine chromosomes for GL, GW, and % chalk. These 15 QTLs were further characterized and scanned for natural genetic variation in a japonica diversity panel (JDP) to identify candidate genes for GL, GW, and %chalk. We found 6160 high impact single nucleotide polymorphisms (SNPs) characterized as such depending on their type, region, functional class, position, and proximity to the gene and/or gene features, and 149 differentially expressed genes (DEGs) in the 51 Mbp genomic region comprising of the 15 QTLs. Out of which, 11 potential candidate genes showed high impact SNP associations. Therefore, the analysis of the mapped QTLs and their genetic dissection in the US grown Japonica rice genotypes at genomic and transcriptomic levels provide deep insights into genetic variation beneficial to rice breeders and geneticists for understanding the mechanisms related to grain quality under heat stress in rice.

Introducción: La tuberculosis es una enfermedad infecciosa altamente prevalente en todo el mundo. Objetivo: Determinar la utilidad diagnóstica de M. tuberculosis por la técnica de reacción en cadena de la polimerasa (PCR) en pacientes de un hospital del norte de Perú. Métodos: Las muestras clínicas de los pacientes se procesaron para la extracción de ADN por el método salting out. Para determinar si el patógeno la muestra de esputo pertenece al complejo M. tuberculosis se emplearon los marcadores que amplifican IS6110, se amplificó usando la técnica PCR y luego los productos de PCR se sometieron a una electroforesis en gel de agarosa al 1,5% y visualizados mediante tinción con bromuro de etidio al 1%. El estudio se realizó en el Hospital Regional Lambayeque, Chiclayo, Lambayeque, Perú. Resultados: Se evaluaron 148 muestras de pacientes: 72 (48%) varones y 77 (52%) mujeres. Las edades fluctuaron desde los cinco a los noventa y tres años, con una media de 45,85 años. Se observó que 105 (70%) pacientes resultaron negativos para la prueba de tuberculosis y 44 (30%) positivo. Se detectaron además 24 (55%) pacientes varones que fueron positivos y 20 (45%) pacientes mujeres que fueron negativas. En las muestras que resultaron positivo para TBC se encontraron: 2 (5%) biopsia de absceso, 2 (5%) biopsia de intestino, 17 (39%) lavado bronqueo alveolar, 4 (9%) líquido cefalorraquídeo, 17 (39%) líquido pleural y 2 (5%) líquido peritoneal. Conclusiones: Se puede detectar Mycobacterium tuberculosis en muestras pulmonares y extra pulmonares en pacientes hospitalarios. Palabras clave: Mycobacterium tuberculosis, tuberculosis pulmonar, reacción en cadena de la polimerasa, PCR