Maize (Zea mays L.) is one of the world’s major food crops, and often suffers from tremendous yield loss caused by abiotic stresses. The MADS-box genes are known to play versatile roles in plants, controlling plant responses to multiple abiotic stresses. However, understanding of regulation of their expressions by the conventional loss-of-function approach is very difficult. So far, regulation of MADS-box gene expression is little known. The best approach to retrieve expression regulation of this category of genes is to characterize expression of their promoters. In this study, the promoter of a homolog (GenBank accession no. EC864166) of maize MADS-box gene m18 was cloned by way of genome-walking PCR, named Pro66. Predicative analysis indicated that Pro66 contains more than one TATA box and multiple cis-acting environmental conditions-responsive elements (ECREs). Pro66 could drive expression of the β-glucuronidase (GUS)-encoding gene in maize, and heterologous expression of GUS in red pepper stressed by water deficit, salt, copper, iron deficiency, heat, cold, and grown under short and long photoperiods, echoing predicative ECREs. Conclusively, maize MADS-box gene m18 likely plays versatile functions in maize response to multiple abiotic stresses due to the promoter with multiple cis-acting elements. The complex arrangement of multiple cis-acting elements in the promoter features meticulously regulated expression of m18. The results give informative clues for heterologous utilisation of the promoters in monocot and dicot species. The copy of the ECREs and heterologous expression of the promoter in dicot species are also discussed.

Genetic and metabolic engineering approaches are powerful tools for improving the tolerance of maize to abiotic stresses because they are faster and can afford greater control over agronomically useful traits. However, in-depth understanding of the molecular mechanisms controlling response to abiotic stresses is the prerequisite for successful implementation of these strategies. A great flaw to dissect the biological mechanisms by genome sequencing is that genome sequencing approach could not reflect real-time molecular actions of plants especially under the stresses because the living organisms rarely live in unchanging environments. Post-genomics such as transcriptomics, metabolomics, and proteomics can generate knowledge that is closer to the biological processes. With the development of post-genomics, it can be expected that voluminous data will be generated. This paper proposes that future research on maize stress tolerance in the era of post-genomics should focus on metabolomics and proteomics; stress tolerance of whole plant rather than individual tissues or organs; coordination of expression of genes among tissues; characterization of promoters of stress-responsive genes; interrelation between mechanisms for tolerance to, and growth recovery from the stress; hexose metabolism as well as the glycolysis pathway; and foundation genotypes.

Southern rice black-streaked dwarf disease is a new rice disease that severely affects rice production in South China. To understand transmission capacity of the vector Sogatella furcifera to Southern rice black-streaked dwarf virus (SRBSDV) among different host plant species, potential host plants of SRBSDV collected from the diseased rice field and/or adjacent to the field in Hunan Province, China, were determined by RT-PCR, and the transmission rates of SRBSDV by S. furcifera among different host plant species were investigated. The results showed that host plants of SRBSDV in the rice fields were five of family Gramineae (Oryza sativa, Echinochloa crusgalli, Zea mays, Paspalum distichum, Alopecurus aequali) and two of family Cyperaceae (Juncellus serotinus and Cyperus difformis). S. furcifera could not transmit SRBSDV between gramineous plants and cyperaceous plants, and could not transmit SRBSDV between the gramineous plants, J. serotinus and C. difformis as well. However, SRBSDV could be transmitted by S. furcifera within gramineous plants. S. furcifera could transmit SRBSDV between interspecies among three species plants (O. sativa, E. crusgalli and Z. mays), and between P. distichum and A. aequali. At 15, 20, 25, 30, and 35°C, both macropterous and brachypterous adult of S. furcifera could transmit SRBSDV from the plants (e.g., E. crusgalli, Z. mays and O. sativa) infected with SRBSDV to rice seedlings. The transmission rates were first increased and then decreased with the increase of temperature. Macropterous adults transmitted SRBSDV from the viruliferous E. crusgalli, Z. may and rice plants to the healthy rice seedlings, and the infected rates of rice seedlings were 26.2, 18.8 and 23.7% at 15°C, 56.6, 64.6 and 53.6% at 25°C, and was 11.2, 10.2 and 7.3% at 35°C, respectively. Transmission capacity of brachypterous adults was significantly higher than that of macropterous adults at 15, 20 and 25°C (P<0.05), while transmission capacity of brachypterous adults was relatively lower compared with that of macropterous ones at 35°C. These results offer evidence on the transmission of SRBSDV via the vector S. furcifer among different host plants, which can be helpful to control Southern rice black-streaked dwarf disease by the appropriate cultural measures in South China.