Methyl jasmonate alters N partitioning, N reserves accumulation and induces gene expression of a 32‐kDa vegetative storage protein that possesses chitinase activity in Medicago sativa taproots

Abstract

This study presents the effects of methyl jasmonate (MeJA) on growth, N uptake, N partitioning, and N storage in taproots of non-nodulated alfalfa (cv. Lodi). When compared to untreated plants, addition of 100 micro M MeJA to the nutrient solution for 14 days reduced total growth and modified biomass partitioning between shoots and roots in favour of taproots and lateral roots. MeJA decreased N uptake (after 7 days) and increased N partitioning towards roots after 14 days. This preferential N partitioning to roots was accompanied by increased N storage in taproots as soluble proteins. Compared to total soluble proteins, VSP accumulation occurred earlier (7 days), and was greater (2-fold increase) in plants treated with 100 micro M MeJA. Steady-state transcript levels for two VSPs (32 and 57 kDa) also increased markedly (about 4-fold) in roots of plants treated with 100 micro M MeJA. This suggests that MeJA could act directly (transcriptional regulation) or indirectly (via the changes of N partitioning among alfalfa organs) on N storage as soluble proteins and in particular, VSPs. Because the deduced amino acid sequence of the 32 kDa VSP clone reveals high homology with Class III chitinases, we propose that the 32 kDa VSP may have a role in pathogen defense, in addition to its function as a storage protein.

The Potassium-Dependent Transcriptome of Arabidopsis Reveals a Prominent Role of Jasmonic Acid in Nutrient Signaling

“…K 1 -regulated genes encoding vegetative storage proteins and enzymes involved in the biosynthesis and degradation of glucosinolates and polyamines support the notion of altered storage strategies for nitrogen and carbon in K 1 -deficient plants (Staswick, 1984;Rask et al, 2000;Kakkar and Sawhney, 2002). JA-dependent management of nitrogen allocation is in agreement with recent findings that JA treatment of tomato plants decreased nitrogen uptake and altered nitrogen partitioning toward root nitrogen storage (Meuriot et al, 2004). Regulation of K 1 channels by JA (Evans, 2003;Suhita et al, 2003) and polyamines (Brü ggemann et al, 1998;Liu et al, 2000) has been reported and might contribute to K 1 reallocation between cellular compartments and tissues (Amtmann et al, 2004).…”

Arabidopsis Vegetative Storage Protein Is an Anti-Insect Acid Phosphatase

“…Vegetative storage proteins (VSP) are proteinaceous storage reserves that have been identified from numerous plants, such as soybean (Glycine max; Wittenbach, 1983), potato (Solanum tuberosum; Mignery et al, 1984Mignery et al, , 1988, sweet potato (Ipomoea batatas; Maeshima et al, 1985), white clover (Trifolium repens; Goulas et al, 2003), alfalfa (Medicago sativa; Meuriot et al, 2004b), and in the bark of deciduous trees such as poplar (Populus deltoides; Coleman et al, 1991) and elderberry (Sambucus nigra; Van Damme et al, 1997). These proteins can accumulate to a high abundance, up to 50% of the total soluble proteins, in various vegetative storage organs.…”

Diverse chitinases are invoked during the activity-dormancy transition in spruce

“…Although most chitinases characterized as VSPs are GH 19 cluster 4/class III chitinases (Peumans et al 2002;Meuriot et al 2004;Rao and Gowda 2008), a storage function for chitinases belonging to other classes cannot be discounted. There is also the possibility of multi-functional chitinases, such as chitinolytic chitinases that serve as VSPs (Meuriot et al 2004) or chitinolytic chitinases with additional VSP and cold acclimation functions (Avice et al 2003). Chitinolytic chitinases could conceivably even contribute to seasonal N cycling by releasing nitrogen from Nacetylglucosamine-containing endogenous substrates, although this is speculative.…”

“…Franco, Picea abies (L.) Karst., and Picea pungens Engelm., indicating that chitinases play a role in cold hardiness of conifers (Zamani et al 2003;Jarząbek et al 2009). Finally, chitinases have also been recognized as vegetative storage proteins (Clendennen et al 1998;Peumans et al 2002;Meuriot et al 2004).…”