Increasing vulnerability of crops to a wide range of abiotic and biotic stresses can have a marked influence on the growth and yield of major crops, especially sugarcane (Saccharum spp.). In response to various stresses, plants have evolved a variety of complex defense systems of signal perception and transduction networks. Transcription factors (TFs) that are activated by different pathways of signal transduction and can directly or indirectly combine with cis-acting elements to modulate the transcription efficiency of target genes, which play key regulators for crop genetic improvement. Over the past decade, significant progresses have been made in deciphering the role of plant TFs as key regulators of environmental responses in particular important cereal crops; however, a limited amount of studies have focused on sugarcane. This review summarizes the potential functions of major TF families, such as WRKY, NAC, MYB and AP2/ERF, in regulating gene expression in the response of plants to abiotic and biotic stresses, which provides important clues for the engineering of stress-tolerant cultivars in sugarcane.

Sugar cane bagasse ash (SCBA) is an abundant byproduct of the sugar and ethanol industry. SCBA is generally used as a fertilizer or is disposed of in landfills, which has led to intensified environmental concerns. In recent years, SCBA research has mainly been focused on utilization in construction materials due to the abundance and pozzolanic characteristics of SCBA. In this paper, a comprehensive review of the state-of-the-art morphology, physical properties, chemical composition, and mineralogical composition of SCBA is presented. Studies indicate that SCBA is a potentially promising construction material. The applications of SCBA as a pozzolanic material, a new source for preparing alkali-activated binders, aggregates, and fillers in construction materials, are summarized. The impacts of SCBA on fresh and hardened concrete properties are highlighted, including the physical properties, mechanical strength, microstructure, and durability. Key factors that govern pozzolanic activity are discussed in detail, including calcination and recalcination temperatures, and durations, fineness, loss on ignition (LOI), and crystal silicon dioxide. Finally, further research on the optimal and broad utilization of SCBA in construction materials is recommended.

The potential of using vector-free minimal gene cassettes (MGCs) with a double terminator for the enhancement and stabilization of transgene expression was tested in sugarcane biolistic transformation. The MGC system used consisted of the enhanced yellow fluorescent protein (EYFP) reporter gene driven by the maize ubiquitin-1 (Ubi) promoter and a single or double terminator from nopaline synthase (Tnos) or/and Cauliflower mosaic virus 35S (35ST). Transient EYFP expression from Tnos or 35ST single terminator MGC was very low and unstable, typically peaking early (8-16 h) and diminishing rapidly (48-72 h) after bombardment. Addition of a ~260 bp vector sequence (VS) to the single MGC downstream of Tnos (Tnos + VS) or 35ST (35ST + VS) enhanced EYFP expression by 1.25- to 25-fold. However, a much more significant increase in EYFP expression was achieved when the VS in 35ST + VS was replaced by Tnos to generate a 35ST-Tnos double terminator MGC, reaching its maximum at 24 h post-bombardment. The enhanced EYFP expression from the double terminator MGC was maintained for a long period of time (168 h), resulting in an overall increase of 5- to 65-fold and 10- to 160-fold as compared to the 35ST and Tnos single terminator MGCs, respectively. The efficiency of the double terminator MGC in enhancing EYFP expression was also demonstrated in sorghum and tobacco, suggesting that the underlying mechanism is highly conserved among monocots and dicots. Our results also suggest the involvement of posttranscriptional gene silencing in the reduced and unstable transgene expression from single terminator MGCs in plants.

In order to understand the genetic diversity and structure within and between the genera of Saccharum and Erianthus, 79 accessions from five species (S. officinarum, S. spontaneum, S. robustum, S. barberi, S. sinense), six accessions of E. arundinaceus, and 30 Saccharum spp. hybrids were analyzed using 21 pairs of fluorescence-labeled highly poloymorphic SSR primers and a capillary electrophoresis (CE) detection system. A total of 167 polymorphic SSR alleles were identified by CE with a mean value of polymorphic information content (PIC) of 0.92. Genetic diversity parameters among these 115 accessions revealed that Saccharum spp. hybrids were more diverse than those of Saccharum and Erianthus species. Based on the SSR data, the 115 accessions were classified into seven main phylogenetic groups, which corresponded to the Saccharum and Erianthus genera through phylogenetic analysis and principle component analysis (PCA). We propose that seven core SSR primer pairs, namely, SMC31CUQ, SMC336BS, SMC597CS, SMC703BS, SMC24DUQ, mSSCIR3, and mSSCIR43, may have a wide appicability in genotype identification of Saccharum species and Saccharum spp. hybrids. Thus, the information from this study contibites to manage sugarcane genetic resources.