Lesion mimic mutants are powerful tools for unveiling the molecular connections between cell death and pathogen resistance. Various proteins responsible for lesion mimics have been identified; however, the mechanisms underlying lesion formation and pathogen resistance are still unknown. Here, we identify a lesion mimic mutant in rice, lesion mimic leaf 1 (lml1). The lml1 mutant exhibited abnormal cell death and resistance to both bacterial blight and rice blast. LML1 is expressed in all types of leaf cells, and encodes a novel eukaryotic release factor 1 (eRF1) protein located in the endoplasmic reticulum. Protein sequences of LML1 orthologs are conserved in yeast, animals and plants. LML1 can partially rescue the growth delay phenotype of the LML1 yeast ortholog mutant, dom34. Both lml1 and mutants of AtLML1 (the LML1 Arabidopsis ortholog) exhibited a growth delay phenotype like dom34. This indicates that LML1 and its orthologs are functionally conserved. LML1 forms a functional complex with a eukaryotic elongation factor 1A (eEF1A)-like protein, SPL33/LMM5.1, whose mutant phenotype was similar to the lml1 phenotype. This complex was conserved between rice and yeast. Our work provides new insight into understanding the mechanism of cell death and pathogen resistance, and also lays a good foundation for studying the fundamental molecular function of Pelota/DOM34 and its orthologs in plants.

Abstract. Seeds and young seedlings of wheat (Triticum aestivum L.) under exposure to Copper (Cu), lead (Pb) and Zinc (Zn) were studied by employing a hydroponic experiment. Addition of Cu or Pb or Zn to the solution inhibited seed germination, plumule and radicle elongation. The toxic of metals to seed germination parameters can be arranged in the rank order of inhibition as follows: Cu > Pb >> Zn. This study showed the contents of chlorophyll and soluble protein in young seedlings of wheat were decreased after 4 d of all heavy metal treatments. Among the tested metals, the toxic of metal to young seedlings was found similar to seeds. All heavy metal concentrations in seedlings increase with their increase in the medium and the duration of treatments. On the other hand, the results demonstrated that the excess accumulation of Cu in leaf and roots could reduce accumulations of zinc (Zn); the excess accumulation of Pb decreased the levels of Cu or Zn in leaf and roots; the excess accumulation of Zn had no influence on Cu accumulations in leaf and roots.

Better understanding of copper uptake and accumulation regulation in plants is critical to the phytoremediation of copper contaminated soil. This study employed a 30-day pot experiment to assess the relationship between organic ligands and copper accumulation in plants. Hyperaccumulator and nonaccumulator varieties of Commelina communis were used, different organic ligands were applied, and the data of copper accumulation in shoots were collected. The six organic ligands included ethylenediaminetetraacetic acid and organic acids (formic acid, citric acid, malic acid, tartaric acid, and succinic acid). The results showed that organic ligands added to culture increased the copper accumulation both varieties. The results of the copper accumulation in shoots agreed with the study of the root uptake kinetics of copper influx. The addition of organic acids could increase copper accumulation in shoots because the copper influx in roots was increased. The results also indicated that the copper influx of hyperaccumulator roots was higher than that of nonaccumulator roots. This is one of the mechanisms by which a hyperaccumulator could amass large amounts of copper in its shoots. In this accumulation process, little effect on the leaf relative water content was in the hyperaccumulator and nonaccumulator of leaves and normal physiological condition of plants.

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To illustrate the control of harmful cyanobacterial growth and the removal of nutritients from fresh water, three submerged macrophytes were grown in the raw water of Guishui Lake. Lindernia rotundifolia, Hygrophila stricta, and Cryptocoryne crispatula were grown together in situ to assess their effectiveness in nutrient removal in microcosms. Results revealed the inhibitory effects of these species on cyanobacterial growth. In addition, water quality in the planted microcosms showed improvement when compared to the water quality of the unplanted microcosm. At all treatments studied, the chemical oxygen demand in the planted microcosms was lower than that in the unplanted microcosms, and the removal rate of all the nitrogen and phosphate in the planted microcosms was better than that of the microcosm without plants. Our study offers a useful algal control method for the lakes or reservoirs that suffer from harmful cyanobacterial blooms.