Stay-green protein, defective in Mendel's green cotyledon mutant, acts independent and upstream of pheophorbide a oxygenase in the chlorophyll catabolic pathway

Type C stay-green mutants are defined as being defective in the pathway of chlorophyll breakdown, which involves pheophorbide a oxygenase (PAO), required for loss of green color. By analyzing senescence parameters, such as protein degradation, expression of senescence-associated genes and loss of photosynthetic capacity, we demonstrate that JI2775, the green cotyledon (i) pea line used by Gregor Mendel to establish the law of genetics, is a true type C stay-green mutant. STAY-GREEN (SGR) had earlier been shown to map to the I locus. The defect in JI2775 is due to both reduced expression of SGR and loss of SGR protein function. Regulation of PAO through SGR had been proposed. By determining PAO protein abundance and activity, we show that PAO is unaffected in JI2775. Furthermore we show that pheophorbide a accumulation in the mutant is independent of PAO. When silencing SGR expression in Arabidopsis pao1 mutant, both pheophorbide a accumulation and cell death phenotype, typical features of pao1, are lost. These results confirm that SGR function within the chlorophyll catabolic pathway is independent and upstream of PAO

Late Pleistocene leopards as a bone accumulator: taphonomic results from S’Espasa cave and other Iberian key sites

The Pleistocene faunal accumulations documented in caves have commonly been attributed to the activity of humans or carnivores. According to the palaeontological and archaeological literature, cave hyena (Crocuta spelaea) was the main known bone accumulator in karstic environments. However, in recent times, the role of leopards as bone accumulators has been revealed, and recent research has identified this behaviour in the Iberian Pleistocene. Moreover, there are other caves where leopard could have been claimed as an accumulator such as S’Espasa. In this work we present its taphonomic study. This cave was compared with the actualistic studies of leopards. Besides, the site of S’Espasa was compared with the other leopard dens in the Iberian Peninsula. These sites present faunal assemblages composed mainly by leopard (Panthera pardus) and Iberian wild goat (Capra pyrenaica), the bones of this ungulate present a similar pattern of bone modification by carnivores, skeletal survival rate, and bone breakage. These features indicate that goats could have been accumulated by leopards. With the data from this work and the previous ones, we try to establish a pattern that will help in the future to identify other accumulations created by this big cat.Fil: Sauqué Latas, Víctor. Universidad de Zaragoza; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Antropología de Córdoba. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades. Instituto de Antropología de Córdoba; ArgentinaFil: Sanchis, Alfred. Museu de Prehistòria de València; EspañaFil: Madurell Malapeira, Joan. Universitat Autònoma de Barcelona; Españ