Background
Abscisic acid (ABA) plays crucial roles in regulating plant growth and development, especially in responding to abiotic stress. The pyrabactin resistance-like (PYL) abscisic acid receptor ...family has been identified and widely characterized in
Arabidopsis
. However, PYL families in rice were largely unknown. In the present study, 10 out of 13 PYL orthologs in rice (
OsPYL
) were isolated and investigated.
Results
Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis showed that expression of
OsPYL
genes is tissue-specific and display differential response to ABA treatment, implying their functional diversity. The interaction between 10 OsPYL members and 5 protein phosphatase 2C in rice (OsPP2C) members was investigated in yeast two-hybrid and tobacco transient expression assays, and an overall interaction map was generated, which was suggestive of the diversity and complexity of ABA-sensing signaling in rice. To study the biological function of
OsPYLs
, two
OsPYL
genes (
OsPYL3
and
OsPYL9
) were overexpressed in rice. Phenotypic analysis of
OsPYL3
and
OsPYL9
transgenic rice showed that
OsPYLs
positively regulated the ABA response during the seed germination. More importantly, the overexpression of
OsPYL3
and
OsPYL9
substantially improved drought and cold stress tolerance in rice.
Conclusion
Taken together, we comprehensively uncovered the properties of
OsPYLs
, which may be good candidates for the improvement of abiotic stress tolerance in rice.
Cold stress at the booting stage leads to a lower seed setting rate and seriously threatens the production of rice (
L.), which has become a major yield-limiting factor in higher-altitude and ...-latitude regions. Because cold tolerance at the booting stage (CTB) is a complex trait and is controlled by multiple loci, only a few genes have been reported so far. In this study, a function of OsMKKK70 (Mitogen Activated Protein Kinase Kinase Kinase 70) in response to CTB was characterized.
expression was rapidly induced by cold stress at the booting stage.
overexpression (
) plants were more sensitive to cold stress at the booting stage with a lower seed setting and pollen fertility, but there was no significant difference between the
mutant and WT. Considering the effect of functional redundancy, we further tested the CTB response of
and
, the double and triple mutants of
with its closest homologs
and
, and found that
and
displayed significantly increased CTB with a higher seed setting and pollen fertility, indicating that OsMKKK70 negatively regulates rice CTB. Moreover, under the low-temperature (LT) condition, the
mutant had slightly higher Gibberellin (GA) contents, increased expression of GA biosynthesis genes, and lower protein level of OsSLR1 in anthers than those in WT. By contrast,
anther had a lower GA biosynthesis than that of WT. Together, these findings suggest that OsMKKK70 negatively regulates rice CTB by fine-tuning GA levels in anthers.
Savoir ethnobiologique engendré durant les « jeux de conduite de troupeau » dans la société Maasai pastoraliste (sud Kenya). Cet article explore la production du savoir ethnobiologique relatif au ...bétail par les enfants Maasai du sud du Kenya, à travers des jeux de conduite de troupeau. Dans la communauté Maasai qui continue à utiliser et à gérer collectivement les terres, les enfants prennent part activement aux tâches quotidiennes liées au bétail, lesquelles servent de cadre à la production du savoir ethnobiologique. Pendant le jeu, les enfants mettent en pratique et communiquent leurs compétences relatives au bétail, tout en les ajustant aux conditions sociales et environnementales actuelles, et en mettant en scène les relations sociales qu’ils découvrent au fil de leurs tâches quotidiennes. L’étude met en lumière la pertinence du jeu dans la construction du savoir ethnobiologique dans des contextes sociaux pastoraux durant les jeux de bétail. Ce faisant, les enfants contribuent à l’enrichissement des relations homme-bétail-environnement dans la société Maasai actuelle.
This paper explores the generation of livestock-related ethnobiological knowledge of Maasai children in Southern Kenya during their herding games. In the Maasai community where lands are still used and managed communally, children still take active roles in livestock-related daily chores, through which they generate ethnobiological knowledge. During the game, children continue the practice and the communication of livestock-related skills, together with interpretations of current social and natural conditions, and the social relations they had experienced during daily chores. This study highlights the significance of ethnobiological knowledge generation in pastoral social contexts during herding games, through which children enrich the human-livestock-biota relations in current Maasai society.
Conocimiento etnobiológico generado durante los “juegos de conducta de rebaño” en la sociedad pastoral Maasai (sur de Kenia). Este artículo explora la producción de conocimientos etnobiológicos relacionados con el ganado por parte de los niños Maasai en el sur de Kenia, a través de juegos de pastoreo. En las comunidades Maasai que continúan utilizando y gestionando sus tierras colectivamente, los niños participan activamente en las tareas diarias relacionadas con el ganado, que proporcionan un marco para la producción de conocimiento etnobiológico. Durante el juego, los niños siguen practicando la comunición y las habilidades ganaderas, mientras interpretan las condiciones sociales y ambientales actuales, y retratan las relaciones sociales que descubren a medida que desarrollan su vida cotidiana. El estudio destaca la relevancia del juego en la construcción del saber etnobiológico en un contexto social pastoral durante los juegos de conducta de rebaño. Al hacerlo, los niños contribuyen al enriquecimiento de las relaciones hombre–ganado–medio ambiente en la sociedad Maasai actual.
Low-temperature germination (LTG) is an important agronomic trait for rice (Oryza sativa). Japonica rice generally has greater capacity for germination at low temperatures than the indica ...subpopulation. However, the genetic basis and molecular mechanisms underlying this complex trait are poorly understood. Here, we report that OsUBC12, encoding an E2 ubiquitin-conjugating enzyme, increases low-temperature germinability in japonica, owing to a transposon insertion in its promoter enhancing its expression. Natural variation analysis reveals that transposon insertion in the OsUBC12 promoter mainly occurs in the japonica lineage. The variation detected in eight representative two-line male sterile lines suggests the existence of this allele introgression by indica-japonica hybridization breeding, and varieties carrying the japonica OsUBC12 locus (transposon insertion) have higher low-temperature germinability than varieties without the locus. Further molecular analysis shows that OsUBC12 negatively regulate ABA signaling. OsUBC12-regulated seed germination and ABA signaling mainly depend on a conserved active site required for ubiquitin-conjugating enzyme activity. Furthermore, OsUBC12 directly associates with rice SUCROSE NON-FERMENTING 1-RELATED PROTEIN KINASE 1.1 (OsSnRK1.1), promoting its degradation. OsSnRK1.1 inhibits LTG by enhancing ABA signaling and acts downstream of OsUBC12. These findings shed light on the underlying mechanisms of UBC12 regulating LTG and provide genetic reference points for improving LTG in indica rice.
Rice is a staple food for more than half of the human population.It has been estimated that by 2030,40%more rice needs to be produced in order to meet the growing demand（Khush,2005）.One of the ...strategies to improve rice productivity is to enlarge rice growth areas, such as the northward expansion of the growth region in Heilongjiang Province, the northernmost region of China （Li et al., 2015）. However, the northward cultivation is accompanied with daylength extension and temperature decrease, which are unfavor- able for rice, a tropical short-day plant, to complete flowering and seed setting. Thus, the need for early-maturing rice cultivars with extremely low photoperiod sensitivity is urgent.
Grain size and leaf angle are key agronomic traits that determine final yields in rice. However, the underlying molecular mechanisms are not well understood. Here we demonstrate that the Oryza sativa ...Mitogen Activated Protein Kinase Kinase Kinase OsMKKK70 regulates grain size and leaf angle in rice. Overexpressing OsMKKK70 caused plants to produce longer seeds. The osmkkk62/70 double mutant and the osmkkk55/62/70 triple mutant displayed significantly smaller seeds and a more erect leaf angle compared to the wild type, indicating that OsMKKK70 functions redundantly with its homologs OsMKKK62 and OsMKKK55. Biochemical analysis demonstrated that OsMKKK70 is an active kinase and that OsMKKK70 interacts with OsMKK4 and promotes OsMAPK6 phosphorylation. In addition, the osmkkk62/70 double mutant showed reduced sensitivity to Brassinosteroids (BRs). Finally, overexpressing constitutively active OsMKK4, OsMAPK6, and OsWRKY53 can partially complement the smaller seed size, erect leaf, and BR hyposensitivity of the osmkkk62/70 double mutant. Taken together, these findings suggest that OsMKKK70 might regulate grain size and leaf angle in rice by activating OsMAPK6 and that OsMKKK70, OsMKK4, OsMAPK6, and OsWRKY53 function in a common signaling pathway that controls grain shape and leaf angle.
The closely related MAP kinase kinase kinases OsMKKK70, OsMKKK55, and OsMKKK 62 play redundant roles in regulating seed size, flag leaf angle and brassinosteroid sensitivity. OsMKKK70 interacts with the MAP kinase kinase OsMKK4 and promotes OsMAPK6 activity, and might function in same pathway as the OsMKK4–OsMAPK6–OsWRKY53 signaling cascade.
The activity of a simple, commercially available copper salt, Cu(NCMe)4(BF4) in intramolecular hydroamination reactions of alkynes and allenes is presented. Reactions were successfully carried out in ...technical acetonitrile in the presence of air. While attempts of alkene hydroamination failed, this catalyst was also found active in intermolecular aza‐Michael reactions.
A simple yet performing copper‐based catalytic system for intramolecular hydroaminations and intermolecular conjugate additions is reported.
Heading date is a key trait in rice domestication and adaption, and a number of quantitative trait loci（QTLs）have been identified. The rice（Oryza sativa L.） cultivars in the Heilongjiang Province, ...the northernmost region of China,have to flower extremely early to fulfill their life cycle.However, the critical genes or different gene combinations controlling early flowering in this region have not been determined. QTL and candidate gene analysis revealed that Hd2/Ghd7.1/Os PRR37 plays a major role in controlling rice distribution in Heilongjiang. Further association analysis with a collection of rice cultivars demonstrated that another three major QTL genes（Hd4/Ghd7, Hd5/DTH8/Ghd8, and Hd1）also participate in regulating heading date under natural long day（LD） conditions. Hd2/Ghd7.1/Os PRR37 and Hd4/Ghd7 are two major QTLs and function additively. With the northward rice cultivation, the Hd2/Ghd7.1/Os PRR37 and Hd4/Ghd7 haplotypes became non-functional alleles. Hd1 might be non-functional in most Heilongjiang rice varieties,implying that recessive hd1 were selected during local rice breeding. Non-functional Hd5/DTH8/Ghd8 is very rare, but constitutes a potential target for breeding extremely early flowering cultivars. Our results indicated that diverse genetic combinations of Hd1, Hd2, Hd4, and Hd5 determined the different distribution of rice varieties in this northernmost province of China.
Brassinosteroids (BRs) are plant‐specific steroid hormones which regulate plant growth, development, and adaptation. Transcriptional regulation plays key roles in plant hormone signaling. A mediator ...can serve as a bridge between gene‐specific transcription factors and the RNA polymerase machinery, functioning as an essential component in regulating the transcriptional process. However, whether a mediator is involved in BR signaling is unknown. Here, we discovered that Oryza sativa mediator subunit 25 (OsMED25) is an important regulator of rice BR signaling. Phenotypic analyses showed that the OsMED25‐RNAi and osmed25 mutant presented erect leaves, as observed in BR‐deficient mutants. In addition, the OsMED25‐RNAi and osmed25 mutant exhibited decreased BR sensitivity. Genetic analysis indicated that OsMED25‐RNAi could suppress the enhanced BR signaling phenotype of Osbzr1‐D. Further biochemical analysis showed that OsMED25 interacts with OsBZR1 in vivo, and OsMED25 is enriched on the promoter of OsBZR1 target genes. RNA sequencing analysis indicated that OsMED25 affects the expression of approximately 45% of OsBZR1‐regulated genes and mainly functions as a corepressor of OsBZR1. Together, these findings revealed that OsMED25 regulates rice BR signaling by interacting with OsBZR1 and modulating the expression of OsBZR1 target genes, thus expanding our understanding of the roles of mediators in plant hormone signaling.
Plant hormone BR controls the rice architecture and final yield. Ideal plant architecture of rice can be bred via manipulating BR signaling. We show that OsMED25 regulates rice BR signaling by interacting with OsBZR1 and modulating the expression of OsBZR1 target genes, which provide a putative target for engineering breeding.
PDF
