Striking a growth–defense balance:Stress regulators that function in maize development

Maize(Zea mays)cultivation is strongly affected by both abiotic and biotic stress,leading to reduced growth and productivity.It has recently become clear that regulators of plant stress responses,including the phytohormones abscisic acid(ABA),ethylene(ET),and jasmonic acid(JA),together with reactive oxygen species(ROS),shape plant growth and development.Beyond their well established functions in stress responses,these molecules play crucial roles in balancing growth and defense,which must be finely tuned to achieve high yields in crops while maintaining some level of defense.In this review,we provide an in-depth analysis of recent research on the developmental functions of stress regulators,focusing specifically on maize.By unraveling the contributions of these regulators to maize development,we present new avenues for enhancing maize cultivation and growth while highlighting the potential risks associated with manipulating stress regulators to enhance grain yields in the face of environmental challenges.

SWOT Analysis and Development Strategies of Maize Industry in Heilongjiang Province

With the development of China＇s market economy, the international grain supply situation is increasingly tense, and the grain has been regarded as an important international strategic resource in the international market. Due to the reduction of international grain output and expected inflation, the gap between maize supply shortage and increasing demand is apparent in China, so that China is described as a worrying importer country. By using SWOT analysis belonging to the field of enterprise strategic management, this paper analyzed the current maize industry development in Heilongjiang Province as an entry point, the strength, weakness and opportunity and threat were put forward. Thereby, the developing principles and strategies were proposed to stimulate the maize industry development in Heilongjiang Province, which would lay a good foundation of 50 billion kilograms grain production capacity by 2015 in China, as well as the economic development and local farmers＇ income increase.

Recent Development in Maize Research at Institute for Agricultural Research, Samaru, Nigeria

Maize research at Institute for Agricultural Research, Samaru, Nigeria resulted in sustained growth in yields in the last two decades. Maize is grown throughout the country with guinea savanna as the most important maize growing zone. In the last five years, four new open pollinating varieties developed in collaboration with the International Institute of Tropical Agriculture （IITA, Ibadan） had been released for production. Hybrid varieties are also marketed by seed companies. The research was focused on variety improvement, improved management practices, integrated pests and disease control, soil fertility management, on-farm testing of improved production packages and socio-economics of production as well as adoption studies. The recently released quality protein maize has improved the nutritional status of vulnerable groups. Drought tolerant maize for Africa research project has contributed to sustainable maize production, poverty reduction and food security in the continent.

Defective Kernel 39 encodes a PPR protein required for seed development in maize

RNA editing is a posttranscriptional process that is important in mitochondria and plastids of higher plants. All RNA editing-specific trans-factors reported so far belong to PLS-class of pentatricopeptide repeat(PPR)proteins. Here, we report the map-based cloning and molecular characterization of a defective kernel mutant dek39 in maize. Loss of Dek39 function leads to delayed embryogenesis and endosperm development, reduced kernel size, and seedling lethality. Dek39 encodes an E subclass PPR protein that targets to both mitochondria and chloroplasts, and is involved in RNA editing in mitochondrial NADH dehydrogenase3(nad3) at nad3-247 and nad3-275. C-to-U editing of nad3-275 is not conserved and even lost in Arabidopsis, consistent with the idea that no close DEK39 homologs are present in Arabidopsis. However, the amino acids generated by editing nad3-247 and nad3-275 are highly conserved in many other plant species, and the reductions of editing at these two sites decrease the activity of mitochondria NADH dehydrogenase complex I,indicating that the alteration of amino acid sequence is necessary for Nad3 function. Our results indicate that Dek39 encodes an E sub-class PPR protein that is involved in RNA editing of multiple sites and is necessary for seed development of maize.