A window into fungal endophytism in Salicornia europaea: deciphering fungal characteristics as plant growth promoting agents

Aim Plant-endophytic associations exist only when equilibrium is maintained between both partners. This study analyses the properties of endophytic fungi inhabiting a halophyte growing in high soil salinity and tests whether these fungi are beneficial or detrimental when non-host plants are inoculated. Method Fungi were isolated from Salicornia europaea collected from two sites differing in salinization history (anthropogenic and naturally saline) and analyzed for plant growth promoting abilities and non-host plant interactions. Results Most isolated fungi belonged to Ascomycota (96%) including dematiaceous fungi and commonly known plant pathogens and saprobes. The strains were metabolically active for siderophores, polyamines and indole-3-acetic acid (mainly Aureobasidium sp.) with very low activity for phosphatases. Many showed proteolytic, lipolytic, chitinolytic, cellulolytic and amylolytic activities but low pectolytic activity. Different activities between similar fungal species found in both sites were particularly seen for Epiccocum sp., Arthrinium sp. and Trichoderma sp. Inoculating the non-host Lolium perenne with selected fungi increased plant growth, mainly in the symbiont (Epichloë)-free variety. Arthrinium gamsii CR1-9 and Stereum gausapatum ISK3-11 were most effective for plant growth promotion. Conclusions This research suggests that host lifestyle and soil characteristics have a strong effect on endophytic fungi, and environmental stress could disturb the plant-fungi relations. In favourable conditions, these fungi may be effective in facilitating crop production in non-cultivable saline lands

Coping With Metal Toxicity – Cues From Halophytes

Being the native flora of saline soil, halophytes are well studied for their salt tolerance and adaptation mechanism at the physiological, biochemical, molecular and metabolomic levels. However, these saline habitats are getting contaminated due to various anthropogenic activities like urban waste, agricultural runoff, mining, industrial waste that are rich in toxic metals and metalloids. These toxic metals impose detrimental effects on growth and development of most plant species. Halophytes by virtue of their tolerance to salinity also show high tolerance to heavy metals which is attributed to the enhanced root to shoot metal translocation and bioavailability. Halophytes rapidly uptake toxic ions from the root and transport them toward aerial parts by using different transporters which are involved in metal tolerance and homeostasis. A number of defense related physiological and biochemical strategies are known to be crucial for metal detoxification in halophytes however; there is paucity of information on the molecular regulators. Understanding of the phenomenon of cross-tolerance of salinity with other abiotic stresses in halophytes could very well boost their potential use in phytoremediation. In this article, we present an overview of heavy metal tolerance in case of halophytes, associated mechanisms and cross-tolerance of salinity with other abiotic stresses

Improvement of Soybean Crop for Yield, Stress Tolerance, and Value-Added Products Using a Transgenic Approach

Soybean (Glycine max) is an economically important crop, ranking first among the edible oilseed crops in the world due to its oil content and nutritional value. Besides, it is used as a dietary supplement and a source of pharmaceuticals. The recent rapid climate changes and increasing global population have led to increasing demand for vegetable oil. In the recent past, advances in the field of plant biotechnology have revolutionized agricultural practices at a global level to enhance the yield of crops. This technology not only makes an impact on the agricultural market but also opens up new corridors for agriculture-related industrial applications of this important crop. Therefore, in the last two decades, soybean has gained attention for genetic improvement with remarkable developments in the manipulations of genes for the induction of desired characteristics. In this review, we introduced the transgenic approach as a promising tool for the improvement of soybean oilseed quality and productivity. Then, the enhancement of nutritional and pharmaceutical value together with biotic and abiotic stress-resistant ability was summarized and compared. The methods and strategies for achieving soybean crops with improved abiotic stress tolerance, productivity, and pharmaceutics are categorized to help with future research

Temporal and spatial changes in ion homeostasis, antioxidant defense and accumulation of flavonoids and glycolipid in a halophyte <i>Sesuvium portulacastrum</i> (L.) L.

<div><p>Salinity is an important environmental constraint limiting plant productivity. Understanding adaptive responses of halophytes to high saline environments may offer clues to manage and improve salt stress in crop plants. We have studied physiological, biochemical and metabolic changes in a perennial, fast growing halophyte, <i>Sesuvium portulacastrum</i> under 0 mM (control), 150 mM (low salt, LS) and 500 mM (high salt, HS) NaCl treatments. The changes in growth, relative water content, cation, osmolyte accumulation, H₂O₂ and antioxidant enzyme activity (SOD, CAT and APX) were observed under different treatment conditions. A positive correlation was revealed for sodium ion accumulation with malondialdehyde (r² = 0.77), proline (r² = 0.88) and chlorophyll content (r² = 0.82) under salt treatment while a negative correlation was observed with relative tissue water content (r² = -0.73). The roots and leaves showed contrasting accumulation of potassium and sodium ions under LS treatment. Temporal and spatial study of sodium and potassium ion content indicated differential accumulation pattern in roots and leaves, and, high potassium levels in root. Higher H₂O₂ content was recorded in roots than leaves and the antioxidant enzyme activities also showed significant induction under salt treatment conditions. Gene expression profiling of sodium transporters, <i>Sodium proton exchanger</i> (<i>NHX3</i>), <i>Vacuolar ATPase</i> (<i>vATPase</i>) and <i>Salt overly sensitive1</i> (<i>SOS1</i>) showed up regulation under salt stress after 6–24 hr of NaCl treatment. Metabolite changes in the salt stressed leaves showed increased accumulation of flavonoids (3,5-dihydroxy-6,4’-dimethoxy-flavone-7-O-[α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside], and3,5-dihydroxy-6,3’,4’-trimethoxy-flavone-7-O-[α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside] in both LS and HS treatments, while a glycolipid, 1-O-linolenyl-2-O-(palmitoyl)-3-O-galactopyranosyl glycerol, accumulated more in LS over HS treatments and control. The results suggest that differential spatial and temporal cation levels in roots and leaves, and accumulation of flavanoid and glycolipid could be responsible for salt adaptation of <i>S</i>. <i>portulacastrum</i>.</p></div

Effect of different NaCl treatments on MDA content of roots and leaves of <i>S</i>. <i>portulacastrum</i>.

<p>Different letters over bar with same color indicates significant difference in treatment according to Duncan's multiple range test DMRT <i>p</i>≤ 0.05).</p

Temporal and spatial changes in ion homeostasis, antioxidant defense and accumulation of flavonoids and glycolipid in a halophyte <i>Sesuvium portulacastrum</i> (L.) L. - Fig 8

<p>Effect of different NaCl) treatments on sodium, potassium and calcium ion content A) in roots, B) in leaves of <i>S</i>. <i>portulacastrum</i>. Different letters over bar with same color indicates significant difference in treatment according to Duncan's multiple range test DMRT <i>p</i>≤ 0.05).</p

Effect of different NaCl treatments on proline content in roots and leaves of <i>S</i>. <i>portulacastrum</i>.

<p>All the values are means ±S.E. (n = 3). Different letters over bar with same color indicates significant difference in treatment according to Duncan's multiple range test (DMRT p≤ 0.05).</p

Temporal and spatial changes in ion homeostasis, antioxidant defense and accumulation of flavonoids and glycolipid in a halophyte <i>Sesuvium portulacastrum</i> (L.) L. - Fig 1

<p>A) Effect of different NaCl treatments on growth of <i>S</i>. <i>portulacastrum</i>. C-control 0 mM NaCl), LS-Low salt 150 mM NaCl), HS-High salt 500 mM NaCl). B) Effect of salinity treatments on fresh weight of <i>S</i>. <i>portulacastrum</i> plants. Different letters over bar indicates significant difference between treatment according to Duncan’s multiple range test <i>p</i>≤ 0.05).</p

Temporal and spatial changes in ion homeostasis, antioxidant defense and accumulation of flavonoids and glycolipid in a halophyte <i>Sesuvium portulacastrum</i> (L.) L. - Fig 9

<p>Time dependant accumulation of A) sodium in roots B) sodium in leaves at 2hr, 6hr, 24 hr, 3d, 5d and 7d in <i>S</i>. <i>portulacastrum</i> under 0, 150 and 500 mM NaCl treatment.</p

Estimation of chlorophyll pigments total chlorophyll, chlorophyll ‘A’ and chlorophyll ‘B’) under different NaCl treatments in <i>S</i>. <i>portulacastrum</i>.

<p>Different letters over bar with same color indicates significant difference in treatment according to Duncan's multiple range test DMRT <i>p</i>≤ 0.05).</p