OsIPK2, a Rice Inositol Polyphosphate Kinase Gene, Is Involved in Phosphate Homeostasis and Root Development

Molecular and physiological characterizations of roots under drought stress in rice: A comprehensive review

Drought stress poses a major challenge to rice (Oryza sativa L.) production, significantly threatening global food security, especially in the context of climate change. Root architecture plays a key role in drought resistance, as rice plants require substantial water throughout their growth. The genetic diversity of rice root systems exhibits various growth patterns and adaptive traits that enable plants to endure water-deficient conditions. Harnessing this diversity to improve drought resilience demands a thorough understanding of critical root traits and adaptive mechanisms. This review explores rice roots' anatomical, physiological, and biochemical responses to drought, emphasizing important traits such as root architecture, xylem vessel modifications, root cortical aerenchyma (RCA), and water transport mechanisms. The role of biochemical regulators, including phytohormones, sugars, lipids, and reactive oxygen species (ROS), in root adaptation to drought is also explored. Additionally, the genetic and molecular pathways influencing root development under drought stress are discussed, with a focus on key genes and transcription factors (TFs) such as NAC, bZIP, AP2/ERF, and others that contribute to enhanced drought tolerance. Understanding these complex interactions is crucial for breeding drought-tolerant rice varieties, ultimately improving crop productivity under challenging environmental conditions.

Origin, evolution, and diversification of inositol 1,4,5-trisphosphate 3-kinases in plants and animals

BACKGROUND

In Eukaryotes, inositol polyphosphates (InsPs) represent a large family of secondary messengers and play crucial roes in various cellular processes. InsPs are synthesized through a series of pohophorylation reactions catalyzed by various InsP kinases in a sequential manner. Inositol 1,4,5-trisphosphate 3-kinase (IP3 3-kinase/IP3K), one member of InsP kinase, plays important regulation roles in InsPs metabolism by specifically phosphorylating inositol 1,4,5-trisphosphate (IP3) to inositol 1,3,4,5-tetrakisphosphate (IP4) in animal cells. IP3Ks were widespread in fungi, plants and animals. However, its evolutionary history and patterns have not been examined systematically.

RESULTS

A total of 104 and 31 IP3K orthologues were identified across 57 plant genomes and 13 animal genomes, respectively. Phylogenetic analyses indicate that IP3K originated in the common ancestor before the divergence of fungi, plants and animals. In most plants and animals, IP3K maintained low-copy numbers suggesting functional conservation during plant and animal evolution. In Brassicaceae and vertebrate, IP3K underwent one and two duplication events, respectively, resulting in multiple gene copies. Whole-genome duplication (WGD) was the main mechanism for IP3K duplications, and the IP3K duplicates have experienced functional divergence. Finally, a hypothetical evolutionary model for the IP3K proteins is proposed based on phylogenetic theory.

CONCLUSION

Our study reveals the evolutionary history of IP3K proteins and guides the future functions of animal, plant, and fungal IP3K proteins.